A car registration valuation plate estimate puts a rough worth on a registration number, the private plate (or cherished number plate) that a vehicle displays, not on the car itself. The Driver and Vehicle Licensing Agency (DVLA) records every registration and sells personalised ones, but it does not publish a value for yours, so the figure comes from comparable sales, auction results and what buyers will pay.
Part of Plate Valuation & Sales. Start with the main guide: Value My Number Plate Instantly
Updated October 2026 · Independent information, not legal advice
The cost side is just as confusing as the value side. People ask what a new plate costs, what a transfer costs and why cheap registrations exist, and the honest answer is that most amounts are set by the seller, the supplier or the DVLA at the time. What follows sorts registrations into categories, explains how each is valued, and shows how to compare evidence without trusting a single number.
What Does A Car Registration Valuation Involve?
A car registration valuation compares your registration with similar ones that have actually sold, then adjusts for the features that make yours stronger or weaker. It is a research exercise, not a lookup.
The registration, not the car
The vehicle can be worth far more or far less than the number on it. A car valuation looks at make, age, mileage and condition. A plate valuation looks at characters, format and demand.
What you need before you start
- The exact registration, including spacing.
- Its format: dateless, prefix, suffix or current style.
- Whether it is on a vehicle or held on a V778 retention document or V750 certificate of entitlement.
- The date of any retention, so you know whether it is still valid.
How Are Different Kinds Of Plate Valued?
Each category has its own logic. A short dateless plate is judged on scarcity, an initials plate on who wants those initials, a humorous plate on how many people find it funny, and a long current-style plate on very little at all.
- Short dateless: scarcity and clean reading.
- Initials and names: size of the audience that shares them.
- Humorous plates: appeal and the plate's legal reading.
- Prefix and suffix: reading, plus the vehicle age they fit.
- Current style: how well the last three letters read.
What About 4 Digit Number Plates?
4 digit number plates, such as a dateless registration with one to three letters and a four-digit number, sit in a popular band of the market and are valued on the letters, the digits and how neatly the two read together. Four digits are more plentiful than one or two, so these are usually less scarce than the shortest registrations.
What to compare
Look at plates with the same letter count and similar digit patterns. Repeated numbers, round numbers and years usually draw more interest than random ones.
What to avoid
Do not compare a four-digit plate with a one-digit one. They belong to different parts of the market, and the gap between them can be very large.
Where four digits sit in the market
A four-digit plate with one letter sits close to the premium end of this band, while one with three letters and a long number is more ordinary. Judge each by its letter count first.
How Are Short Dateless Plates Valued?
Short dateless plates, with one to three letters and one to four numbers, are the part of the market that many collectors follow, because there is a limited supply and they fit almost any vehicle. See dateless number plates.
One, two and three letters
The fewer the characters, the scarcer the plate. A one-letter plate is a different category from a three-letter one, and the valuation approach should reflect it.
Fit with the vehicle
Because a dateless plate does not show age, it can go on a wide range of vehicles. That keeps the pool of buyers broad.
Why collectors follow them
Collectors treat short dateless plates as a category of their own, so results from this band are watched closely. Sales here are good evidence for similar plates but poor evidence for anything else.
How Do Three-Letter Plates Fit In?
A plate with a block of three letters can be a dateless plate, a prefix or suffix plate, or the tail of a current-style registration. Valuation depends on which it is. The format guide for 3 letter number plates explains the layouts, and a buyer will check the layout before the letters.
Layout before letters
A buyer asks three questions in order: what is the format, what vehicle does it fit, and does it read well. If the answer to the first two is unclear, the valuation will be discounted.
Do Initials And Fancy Numbers Raise A Valuation?
Initials and fancy numbers raise a valuation when they match what lots of buyers want. A plate that carries a popular pair of initials, a round number or a repeated digit tends to attract more interest than a random mix.
Matching initials
The audience is the people who share the initials. Common initials may reach more buyers, but the supply of similar plates may also be higher.
Initials with a story
Initials that belong to a well-known business or brand are rarely sold to the general public at a normal market rate, so be careful about using comparisons from unrelated plates.
Fancy numbers
Repeated digits, ascending runs and meaningful years are common examples. They can add appeal, but only if the rest of the plate reads well.
What Makes Funny Private Plates Valuable?
Funny private plates are valued on how many people understand and enjoy the joke, and whether the reading is clear at a glance. A joke that needs explaining rarely sells well. They are also subject to legal and taste limits, because the DVLA does not issue offensive combinations.
Funny number plates for sale
When you see funny number plates for sale, check the plate is a genuine registration with proper paperwork, not a novelty item. A novelty or show plate is not a registration.
- A genuine registration has paperwork recorded with the DVLA.
- A novelty plate is a decorative item with no legal standing on the road.
- A show plate is for display only and may not be used in place of road plates. Ideas and limits are covered in funny number plates.
Funny license plates UK and the law
Funny license plates UK drivers choose must still meet the legal rules: standard font, correct spacing and no altering of characters. A clever reading cannot rely on illegal styling.
When a joke becomes a problem
If the joke only works when the spacing is altered or characters are modified, it falls foul of the rules. The registration itself must carry the reading, and the legal font and spacing must stay untouched.
How Do Prefix And Suffix Plates Differ In Valuation?
Prefix (1983 to 2001) and suffix (1963 to 1983) plates are valued mainly on reading and on the vehicle age that fits. The year letter limits which cars can carry them.
- Prefix plates with a short number and clear letters are the most sought.
- Suffix plates with initials and a low number can stand out.
- Plates that look older than the car are generally fine; plates that look newer are not.
How the age rule limits buyers
The age identifier or year letter tells a story about the vehicle. A plate that makes a car look younger is not allowed, which is why a prefix or suffix plate can have fewer eligible vehicles than a dateless one.
The number plate year chart shows how the year letters map to dates.
How Are Current-Style Plates Valued?
Current-style plates are issued in large numbers, so most are modest in value, and the exceptions are those whose letters spell something or whose digits and letters read as a name. The last three letters are random, so the only value is in the combination.
Where current-style value comes from
- Initials in the last block.
- A word or name made from the last three letters.
- A memory tag and age identifier that suit a newer car.
- Combinations that read well as a whole.
What Are Cherished Number Plates For Sale?
Cherished number plates for sale are registrations offered by the DVLA, auction houses, dealers and private owners. A listing is an asking price, not a result, so use it as a guide only. See cherished plates for the background.
Asking price versus sold price
A listing that has been up for weeks may be priced too high. A lot that sold quickly may have been priced well.
What a genuine listing shows
It identifies the registration, the format and the paperwork, and the seller explains fees.
What a doubtful listing looks like
- No mention of paperwork.
- Pressure to pay before the details are confirmed.
- A price that never changes while similar plates move.
What Are Cheap Private Number Plates?
Cheap private number plates are registrations that sellers price low because demand is limited. That typically means long, hard to read or random combinations. See private number plates under 500 for budget routes without figures.
Cheap private registration numbers
Cheap private registration numbers are rarely a bargain unless the combination suits you personally. Their resale appeal is limited.
When a cheap plate makes sense
A cheap plate suits a driver who wants a personal reading and is not thinking about resale. Keep the expectations realistic and the paperwork safe.
What you give up
- Readability.
- Scarcity.
- Easy resale.
Are Cheap Reg Plates And Low Cost Registration Plates The Same?
Cheap reg plates and low cost registration plates usually refer to the registration number, not the physical plate. The number can be low in price because it is common, while the physical plate has its own, separate cost from a supplier. The supply of number plates is restricted to registered suppliers, whereas the numbers themselves, known as DVLA personalised registrations, are sold by the DVLA, dealers and private sellers.
Two prices in one phrase
When a search says cheap plates, check whether it means the registration or the supplier's price for the plate. Mixing them leads to wrong comparisons, and people who type cheap plates number into a search often want a low-cost registration rather than a plate maker.
What Are The Cheapest Number Plates?
The cheapest number plates in terms of registration are often the long, plain ones, while the cheapest physical plates are ordinary ones from a registered supplier. Neither is automatically better. Legal compliance matters more than saving, and a plate that fails the standard can lead to a fine.
What a legal plate must have
A plate that meets the standard is reflective, uses the legal typeface, has the supplier's details and the British Standard marking, and is made by a registered number plate supplier after proof of identity and entitlement.
Cheap Car Registration Number Plates: What Do They Mean?
Cheap car registration number plates can mean either an inexpensive registration or inexpensive physical plates. Always ask which one is being offered, and what is and is not included.
Questions to ask a seller
- Is the price for the registration, the plates or both?
- Are DVLA fees included?
- Is postage or fitting extra?
- Do I receive the paperwork?
How Much Do Number Plates Cost?
How much do number plates cost depends on which of three separate things you mean: the registration number itself, the DVLA fee to assign or transfer it, and the physical plates from a registered supplier. Each has its own price, and none is fixed here.
The registration number
Set by the seller. The DVLA sets prices for the registrations it sells, auction houses set reserves and fees, and dealers set their own margin.
The DVLA fee
The DVLA charges to assign, retain or transfer a number. The current amount is on GOV.UK.
The physical plates
A registered number plate supplier charges for making the plates, and the price varies by supplier, plate type and extras.
How Much Is A Number Plate?
How much is a number plate in everyday terms usually means the cost of a new, legal set of plates for a car. That is a supplier price, which varies, and it does not include the registration itself or any DVLA fee. Compare two or three registered suppliers and ask for a total including any fitting or postage.
Where the extras hide
Extras can include a flag, a border, raised characters and fitting kits. A price that looks low may rise once these are added.
How Much Are Registration Plates, And How Much Do Registration Plates Cost?
How much are registration plates for a vehicle you already own? Only the physical plates. How much do registration plates cost for a private registration you do not yet own? The registration, plus fees, plus plates. Ask for each line separately so you can compare.
Why separate lines matter
A single "all-in" price hides which part is expensive. Splitting the cost lets you compare sellers on the same basis and spot unnecessary extras.
- Registration price (if buying a private number).
- DVLA assignment or transfer fee.
- Supplier price for plates.
- Any broker, auction or dealer fees.
How Much For A New Registration Plate?
How much for a new registration plate when yours is lost, cracked or faded? That is a replacement from a registered supplier, who must see proof of identity and entitlement. Ask for the price including any extras, and check that the plate meets the current standard.
When you need a replacement
- A lost or stolen plate.
- A cracked or faded plate that no longer meets the standard.
- A plate damaged in a collision.
What proof the supplier wants
Typically an identity document and a document showing you are entitled to the registration, such as the V5C, V750 or V778.
Why unregistered sellers are a risk
A plate from a seller who is not on the register may fail the standard. That could mean refusals at the MOT or a fine for an illegal plate.
How Much Does It Cost For New Number Plates?
How much does it cost for new number plates varies by supplier, plate type and any extras such as a flag or a green flash. Only a registered supplier may make them.
Extras and what is allowed
Some extras, such as a national flag with the identifier or a green flash for zero-emission vehicles, may be allowed where the rules permit. Check GOV.UK before you order. Ask for a written, itemised price rather than relying on an advertised "from" price, since extras change the total.
How Much Does It Cost To Change Number Plates?
How much does it cost to change number plates depends on what you are changing. Swapping existing plates for new ones costs the supplier's price. Moving a private registration to a different car costs the DVLA's fee plus new plates, and may also cause an insurance change. Check the current DVLA fee on GOV.UK.
- Same number
Insurance changes
Changing the registration on a vehicle usually means telling your insurer, which may or may not change your premium.
- Same number, new physical plates: a supplier cost.
- Different number, same car: DVLA fee plus plates.
- Retaining a number: a DVLA fee and a V778.
Read how to put a private number plate on a car for the process.
How Do I Get A Private Number?
How to get private number registration is a short sequence. You find an available registration, buy it from the DVLA or another seller, assign it to your vehicle and then order plates.
- Search the DVLA's personalised registrations or another seller.
- Check the number suits your vehicle's age.
- Buy the registration and keep the V750 or other proof.
- Assign it to your vehicle through the DVLA.
- Order plates from a registered supplier and fit them.
What the vehicle needs
It must meet the DVLA's current conditions, such as being registered in the UK and having a valid MOT where required. The free number plate check shows MOT and tax status by registration.
Common delays
- Missing V5C details.
- An expired MOT.
- A plate that would make the car look newer.
- Waiting for the DVLA to update the record before ordering plates.
Which Number Plate Ideas Hold Their Appeal?
Number plate ideas that hold appeal are simple, readable and personal: initials, a short word, a lucky number or a year. Test any idea on a friend: if they cannot read it, buyers will struggle too.
Ideas that tend to fade
Puns that rely on obscure references, long strings with several look-alike characters and combinations that need a long explanation are the ones that tend to lose appeal. Choose a plate you will still like next year. The number plate idea generator is a handy starting point.
- Short words that spell clearly.
- Initials with a tidy number.
- Meaningful years and numbers.
- Names that are common and easy to spell.
Do Legal Number Plates Affect Value?
Legal number plates keep the value of the registration because a registration that cannot be lawfully displayed is of little use. Legal license plates UK vehicles carry must be reflective, made to BS AU 145e, use the legal font and show the supplier's details. See legal number plates in the UK.
What makes a plate illegal
Altered spacing, stickers on characters, flip mechanisms, unregistered suppliers and novelty fonts are the common causes.
Why this matters to value
A buyer will pay for a registration they can use. A plate that depends on illegal styling to read properly is not worth more.
What About Plates For Cars Compared With Other Vehicles?
Plates for cars are two plates, white at the front and yellow at the rear, with black characters. Other vehicles have their own rules. A private registration can often go on more than one type of vehicle, but the vehicle must meet the DVLA's conditions.
- Cars and vans: front and rear.
- Motorcycles: usually rear only.
- Trailers: see number plates for trailers.
Do Motorbike Number Plates Have A Different Value?
Motorbike number plates carry the same registration value as any other, but the physical plate is smaller and a bike usually needs a rear plate only. A short registration that suits a bike might be popular with bike owners. See motorbike number plates.
Are Personalised Northern Ireland Number Plates Valued Differently?
Personalised Northern Ireland number plates have their own style, usually letters including I or Z followed by digits, and their own market. The DVLA handles registration and tax for Northern Ireland, while the DVA runs testing. Compare like with like, and do not assume a GB plate is worth the same as a Northern Ireland one.
What to compare
Compare Northern Ireland plates with other Northern Ireland plates, and use sales data from the right market. A GB plate in a different style does not tell you much.
What Should I Know About Number Plates NI?
Number plates NI follow a different format from Great Britain, and a registration in one format cannot always move to a vehicle in the other system. Check current rules on GOV.UK, and read about the Driver and Vehicle Agency.
Moving between GB and Northern Ireland
Eligibility can be limited, so check with the DVLA before agreeing a sale.
Irish plates
An Irish plate is a different system again. See Irish number plates.
How Do I Find Number Plates Near Me?
Number plates near me usually means a registered supplier that makes the physical plates. A local shop can be convenient, but the same rules apply online. Check the supplier's registration, ask what proof it needs and confirm the plates meet BS AU 145e.
Online or local
- Local: easier for urgent replacements.
- Online: wider choice of plate types.
- Either way, the supplier must be registered and must ask for proof. A supplier cannot sell you a registration you are not entitled to, so be prepared with documents.
How Do I Build A Valuation Worksheet?
A worksheet turns research into one comparison, which helps you stay objective.
| Category | What to compare | Key evidence |
|---|---|---|
| Short dateless | Letter and digit count | Recent auction lots |
| Initials | The same or similar initials | Sold plates, written offers |
| Prefix or suffix | Year letter and reading | Past sales of near twins |
| Current style | Last three letters | Listings and sold plates |
| Humorous | Clarity of the joke | Sale results and interest |
How to use it
For each row, note three comparable plates, where you found them, and whether the price is a listing or a sale.
How to read the results
Your plate sits somewhere between the weakest and strongest comparison. State the range, not a single number.
Keeping the worksheet honest
Record whether each comparison is a sale, a listing or an offer. Mixing them is the commonest source of wrong conclusions, since listings are usually higher than sales.
Which Sources Of Evidence Are Strongest?
| Source | Strength | Limitation |
|---|---|---|
| Completed sales | Real prices | Hard to find, may be dated |
| Auction results | Public bidding | Fees and reserves differ |
| DVLA listings | Official, current | Asking prices only |
| Broker quotes | Real offers | They include a margin |
| Online tools | Fast | Often lead generators |
How Do I Read Comparable Sales?
Read a comparable sale by checking that the format, length and meaning match, that the sale is recent, and that the price quoted is the final price after any fees. Be sceptical of claims without dates or sources.
Red flags in comparisons
- Prices with no date.
- Sales of plates that are obviously better.
- Results quoted before fees.
- Match the format first.
- Check the date.
- Confirm whether fees are included.
- Ignore sales of famous plates unless yours is comparable.
What Do DVLA Listings And Auctions Show?
DVLA listings show what the DVLA is currently asking for a combination, and auctions show what bidders paid on the day. Together, they give a view of the market. See DVLA number plate auctions.
Limits of listings
Asking prices are not sale prices, and old listings can be out of date.
Limits of auctions
A single auction can be strong or weak. Look at several.
How Many Quotes Should I Collect?
Collect at least two or three, in writing, from different kinds of buyer: a broker, a dealer and an auction house. Ask whether each is a gross or net figure and what happens if the plate does not sell.
Comparing quotes fairly
Put the quotes in a table: provider, figure, gross or net, fees, time to payment, and conditions. A higher figure with higher deductions may leave you with less than a lower, simpler offer.
Are Valuation Tools Lead Generators?
Some are. A tool that asks for contact details before showing a result may exist to pass you to a seller. That does not make it dishonest, but it means the estimate should be tested.
- Never rely on one tool.
- Avoid tools that demand payment for an estimate.
- Be wary of pressure to act at once.
A safer approach
Use a tool only after you know roughly what you hold, and never share more than a name and email. Any tool that insists on payment before a figure is not an estimate.
What Are The Main Selling Routes In Brief?
The routes are the DVLA's channels for new registrations, auctions, brokers or dealers and private sales. For pros and cons and the process, see how to sell a licence plate and plate valuation and sales.
Which Paperwork Matters In A Valuation?
A plate with clean paperwork is worth more than one that needs fixing. The key documents are the V750 certificate of entitlement, the V778 retention document, the V5C and the V317 application route.
Check the dates
Retention and entitlement documents can expire. Check on GOV.UK before you quote a buyer.
Keep copies
Copies help if a document is lost, but the original is what the DVLA acts on.
If a document is lost
The DVLA has routes for replacing documents. Check GOV.UK, and expect some delay before a sale can complete.
What Is The DVLA Transfer Fee?
The DVLA charges a transfer fee to assign, retain or transfer a registration. The amount changes, so check GOV.UK. Treat it as a cost that either you or the buyer will bear, and agree who pays before the sale.
Who usually pays
That is a matter of agreement between you and the buyer. Write it into the terms so the seller and buyer both know before money changes hands. See how to retain a number plate.
Are Trade Plates Part Of Plate Valuation?
No. A trade plate is issued by the DVLA to eligible motor traders and is not a private registration. It has no resale value as a private plate. See how to get trade plates.
What Are The Tax And Finance Angles?
Tax on a plate sale depends on circumstances, and HMRC or a qualified adviser is the right source. In general terms, records of purchase and sale help, and a business that trades in plates is treated differently from a private owner.
Plates on finance
If the vehicle is on finance, the provider may have rights over it, so check before retaining or moving the number. See private number plates on finance.
Business purchases
A company buying a plate for a company vehicle should discuss treatment with an accountant.
What About Insurance And Display?
When a registration changes, tell your insurer so the policy matches the vehicle. The Motor Insurance Database records cover by registration, and only legal plates should be displayed on the road. A show plate is for display only.
What to tell the insurer
Give the new registration and the date it takes effect, and ask for written confirmation that cover matches. Do not drive until the policy shows the right number.
How Does A Plate Valuation Differ From A Car Valuation?
A plate valuation prices a registration number and a car valuation prices the vehicle, so they should be done separately. A free vehicle lookup gives MOT and tax details for the car, not a value for the number. Read about what a number plate check shows.
Are Famous Plates Good Benchmarks?
Famous registrations are in a class of their own, and comparing yours to them rarely helps. See costliest number plates for context, and note that widely reported sales run into six or seven figures for the most exceptional ones.
What famous plates teach
They show that a plate's value is about demand and meaning, not just characters. They do not give a figure for your plate. See number plate 1 and K1 number plate for examples.
What Are The Common Mistakes In Registration Valuation?
- Trusting a single figure.
- Comparing unlike plates.
- Mixing up the registration price and the supplier's price for plates.
- Forgetting DVLA and seller fees.
- Selling before paperwork is in order.
Mistake: confusing cost with value
What you paid is not what it is worth. A plate bought at a high price may sell for less, and the reverse is possible.
Mistake: ignoring timing
A weak auction day can mislead you. Look at several.
What Myths Surround Plate Value?
- Myth: the DVLA will tell you the value. It sells and records plates but is not a valuation service.
- Myth: all dateless plates are worth a lot. Many are modest.
- Myth: a plate always adds value to a car. A buyer may not want it.
- Myth: online tools are exact. They are estimates.
Quick Checklist Before You Rely On A Valuation
- Do you know the format and the paperwork?
- Do you have three comparable sales or results?
- Do you have more than one written quote?
- Do you know every fee?
- Have you checked the vehicle with a free number plate check?
- Have you read the personalised number plates basics?
Frequently Asked Questions
What is a car registration valuation?
It is an estimate of what a registration number might sell for, based on comparable sales, auction results and quotes. The car valuation plate question is separate from the value of the vehicle. The DVLA records and sells registrations but does not value yours, so use market evidence.
How much do number plates cost?
It depends on whether you mean the registration number, the DVLA fee to assign it, or the physical plates. The registration price is set by the seller, the DVLA charges its own fee, and a registered supplier sets the price of the plates. Ask for each in writing and check the current DVLA fee on GOV.UK.
How much does it cost to change number plates?
Swapping physical plates costs the supplier's price. Moving a private registration to another car also involves a DVLA fee, and perhaps an insurance change. Retaining a number involves a fee and a V778. Check the current DVLA fee on GOV.UK and ask suppliers for a written total.
How much for a new registration plate?
A replacement plate is a supplier price, which varies by plate type and extras. The supplier must be registered and will want to see identity and proof of entitlement. Ask for an itemised quote and check that the plates meet the legal standard.
Are cheap private number plates worth buying?
They can be, if you like the combination, but they usually have limited resale appeal because they are long, random or hard to read. Check every cost, including DVLA fees and plates, and ask the seller for proof of entitlement. Do not buy as an investment.
What are the cheapest number plates?
The cheapest registrations are usually long, plain combinations, and the cheapest physical plates come from registered suppliers. The cheapest option is not always the best. A plate must be legal, so check the supplier is registered and the plate meets the standard.
Are 4 digit number plates valuable?
Some are, but value depends on the letters, the digits and how they read together. Four-digit dateless plates are more common than one or two digit ones, so they tend to sit below the very scarcest. Compare near twins with recent sales.
How do I get a private number?
Find an available registration from the DVLA or another seller, buy it, assign it to your vehicle through the DVLA and order plates from a registered supplier. The vehicle must meet current DVLA conditions, and the number must not make the vehicle look newer than it is.
Are funny number plates for sale legal?
A funny registration is legal if it is a genuine registration issued by the DVLA and displayed on legal plates with the proper font and spacing. A novelty plate that is not a registration, or one with altered characters, is not legal for the road. Offensive combinations are not issued.
Can I use a Northern Ireland plate in Great Britain?
Northern Ireland registrations use a different format, and moves between systems have rules. The DVLA handles registration and tax for Northern Ireland and the DVA runs testing there. Check the current guidance on GOV.UK before agreeing any sale or move.
Do I need a V750 to sell a plate?
You need proof of entitlement, which could be a V750 certificate of entitlement, a V778 retention document or the V5C where the plate is on a vehicle. Check validity dates, because documents can expire, and confirm the rules on GOV.UK.
How do I find number plates near me?
Look for a registered number plate supplier. Many operate online and by post, and a local shop is a convenience. Check their registration, ask what proof they need and confirm the plates will meet BS AU 145e. They cannot supply a plate for a registration you are not entitled to.
Are online valuation tools reliable?
They can be a rough guide, but some are lead generators and estimates can be inflated. Treat them as one input and verify with comparable sales and written quotes. A tool cannot see your paperwork or the buyers.
Do legal number plates affect value?
Indirectly, yes. A registration is only useful if it can be displayed lawfully, so buyers expect legal plates made by a registered supplier. Altered spacing, stickers or novelty fonts can lead to a fine, and they do not add value.
Can I value a plate that is on finance?
You can estimate its worth, but selling or moving it may be complicated by the finance agreement. The provider may have rights over the vehicle, so check the agreement and speak to them before retaining or assigning.
What is the main risk when valuing a registration?
Relying on a single source. Compare recent sales, auction results, DVLA listings and at least two written quotes, and be careful with tools that collect your details. Keep your paperwork in order so the figure you reach can actually be realised.
Official Sources
Rules, fees and deadlines change. Confirm anything that affects your money or legal position with the official service.