If you own a BYD SEALION 7, SEAL, ATTO 3, DOLPHIN or another BYD model in the UK, you may be considering exterior upgrades such as a front lip, rear diffuser, side skirts or rear spoiler.

One of the first questions is usually:

Are BYD body kits legal in the UK?

In most cases, the answer is yes — non-structural exterior modifications can be used on UK roads, provided the vehicle remains safe, roadworthy and compliant with the relevant road and MOT requirements.

However, there is an important difference between installing a bolt-on styling part and making a structural modification to the vehicle.

This guide explains where that line is, what UK owners should check before installing a body kit, when DVLA notification may be required, how modifications can affect the MOT, and what to consider when modifying a BYD SEALION 7.

This guide focuses primarily on vehicles registered in England, Scotland and Wales. Northern Ireland operates a separate vehicle testing system, although many of the underlying road-safety considerations are similar.

Front Bumper Lip for BYD SEALION 7

Give your BYD SEALION 7 a cleaner, sportier look with this front bumper lip. It is designed for the front lower bumper and is a practical choice for accessory shops, installers, and wholesale buyers.

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Quick Answer About All You Want To Know About BYD Body Kit Installation

This normally covers parts such as:

• Front lips
• Splitters
• Side skirts
• Rear diffusers
• Roof spoilers
• Rear spoilers
• Rear wings
• Bumper extensions
• Mirror covers
• Exterior trim
• Non-structural styling panels

What Makes a Body Kit Legal in the UK?

A body kit does not become legal because it has a particular certificate.

For an already registered vehicle, the main questions are whether the modification is safe, secure and non-structural.

1. It Must Not Create a Dangerous Projection

One of the most common questions is:

How far can a front splitter or spoiler stick out?

There is no general UK rule saying that an aftermarket splitter can only extend, for example, 30 mm or 50 mm beyond the original bumper.

In other words, there is no simple rule such as:

“A front splitter may not extend more than 5 cm.”

Instead, the important issue is whether the part is likely to create a danger.

The DVSA MOT manual checks body panels, spoilers, undertrays, mirror housings and bumpers for security and potential injury risk.

A component can receive a Major defect if it is insecure or likely to cause injury. A component that may detach can be classified as Dangerous. (gov.uk)

So a larger splitter is not automatically illegal.

The real problems are:

• sharp or dangerous edges
• poor mounting
• excessive movement
• a part that may detach
• a shape that creates an obvious injury risk

2. Sharp Edges Matter

UK IVA standards give a useful technical reference for exterior projections.

For vehicles undergoing IVA, DVSA uses a 100 mm sphere to assess contactable exterior surfaces.

For certain hard projections:

• projections of 5 mm or more are generally assessed against a minimum 2.5 mm radius
• projections below 5 mm should be blunted. (gov.uk)

However, this does not mean every spoiler or splitter fitted to an existing road car needs formal IVA measurement.

For a normal already-registered vehicle, the more practical MOT question is whether the modification is secure and likely to cause injury.

So the IVA figures are best treated as a useful technical benchmark, not as a separate approval procedure for every body kit.

3. Every Part Must Be Securely Mounted

This is one of the clearest UK requirements.

The MOT manual specifically checks:

• bumpers
• spoilers
• body panels
• other exterior body components

An insecure body component can result in a Major defect.

A component likely to become detached can be classified as Dangerous. (gov.uk)

After installation, check:

• bolts
• clips
• brackets
• adhesive areas
• splitter supports
• spoiler bases
• diffuser mounting points
• side-skirt fixings

A body kit should not move excessively when checked by hand.

4. It Must Not Interfere With Steering or Braking

A modification that adversely affects steering or braking can be considered dangerous under the MOT inspection standard. (gov.uk)

For normal styling parts this is uncommon, but it still matters with:

• very wide side skirts
• wheel-arch extensions
• low splitters
• parts installed near suspension components

After installation, make sure there is enough clearance at full steering lock and throughout normal suspension movement.

5. The Number Plate Must Stay Visible

A replacement bumper or rear diffuser must not obstruct the registration plate.

UK registration numbers must remain correctly displayed and readable.

Incorrect number-plate display can lead to an MOT failure and a fine of up to £1,000. (gov.uk)

If the body kit changes the original plate position, the new position must still meet UK requirements.

6. Lights and Reflectors Must Remain Unobstructed

A body kit should not cover or interfere with:

• headlights
• daytime running lights
• indicators
• tail lights
• reversing lights
• rear fog lights
• reflectors

This is especially important with:

• replacement bumpers
• rear diffusers
• grille replacements
• widebody kits

Changing the actual light units is a separate issue and may involve additional lighting requirements.

7. Cameras and ADAS Sensors Must Still Work

Modern BYD vehicles may have:

• parking sensors
• front cameras
• surround-view cameras
• radar modules
• other ADAS hardware

Before fitting a bumper, lip or large exterior panel, check where these systems are located.

The body kit should not block, move or interfere with them.

After installation, confirm that the relevant systems still operate normally.

Is There a Maximum Size for a Front Lip, Splitter or Spoiler?

For ordinary aftermarket styling parts, there is no general UK rule setting one universal maximum projection in centimetres.

That means there is no simple legal formula such as:

• front lip: maximum 50 mm
• spoiler: maximum 80 mm
• diffuser: maximum 100 mm

The legal focus is instead on safety, roadworthiness and overall vehicle dimensions.

Maximum Vehicle Dimensions

For M1 passenger vehicles, the maximum overall width is generally:

2.55 metres

The maximum overall length for a rigid motor vehicle is generally:

12 metres. (legislation.gov.uk)

A normal front lip, spoiler or side skirt will not usually come close to these limits.

They become more relevant with extreme widebody conversions or unusually large aerodynamic parts.

When Does a Body Kit Become a Structural Modification?

This is the most important dividing line.

A normal cosmetic part attached to the existing vehicle body is different from modifying the vehicle’s actual structure.

DVLA considers structural changes to include modifications to the:

• chassis
• monocoque bodyshell
• frame
• load-bearing support structure. (gov.uk)

Examples include:

• lengthening or shortening the chassis
• widening the structural monocoque
• cutting roof pillars
• removing the roof
• modifying load-bearing subframes
• removing load-bearing support members

The 30 cm Rule

One specific DVLA rule is particularly relevant to installers.

DVLA lists the following as an example of a structural modification:

Making additional holes within 30 cm of a suspension, steering, braking or seatbelt mounting point. (gov.uk)

This does not mean every small mounting hole makes a body kit structural.

It means installers should be careful when drilling into the monocoque near safety-critical areas.

For a conventional cosmetic body kit, it is better to use:

• existing OEM mounting points
• bumper mounting locations
• existing screws
• clips
• brackets
• appropriate automotive adhesive
• non-structural mounting areas

where possible.

Do I Need to Tell DVLA?

Normal Bolt-On Body Kit: Usually No

For a normal non-structural body kit, DVLA notification is generally not required.

DVLA requires updates when certain V5C details change, including:

• vehicle colour
• engine
• fuel type
• seating capacity
• certain body-type changes
• structural chassis or monocoque changes. (gov.uk)

A conventional front lip, side skirt, diffuser or spoiler does not normally change those details.

So for an ordinary bolt-on kit:

There is usually nothing to submit to DVLA.

Structural Modification: Yes

If the work changes the chassis, monocoque or another load-bearing part of the vehicle, the situation changes.

DVLA uses the V627/3 Modified Vehicle Statement for structural modification notifications. (gov.uk)

This can apply when the work includes cutting or altering the structural vehicle body and changing it from the manufacturer’s original specification.

What Documents Do I Need?

For a Normal Non-Structural Body Kit

Normally, no government document package needs to be submitted.

You do not generally need to provide DVLA with:

• TÜV
• ABE
• manufacturer approval
• body-kit homologation
• product test reports
• V627/3
• IVA certification

However, it is sensible to keep basic records.

Useful documents include:

• purchase invoice
• product specification
• compatible model information
• installation instructions
• material information
• before-and-after photos
• installer receipt

These are useful records, not mandatory government approval documents.

For a Structural Modification

For a structural modification, DVLA may require:

• completed V627/3 Modified Vehicle Statement
• current V5C
• MOT evidence, where required
• photographs of the modification
• other supporting evidence requested by DVLA. (gov.uk)

DVLA may also require an inspection depending on the extent of the modification.

Do I Need IVA?

For a normal cosmetic body kit:

No, normally not.

Individual Vehicle Approval is mainly used for vehicles that have been:

• built
• rebuilt
• radically altered
• reconstructed
• imported without the necessary approval. (gov.uk)

Installing a front lip, side skirt, diffuser or spoiler does not automatically make a registered vehicle “radically altered”.

IVA becomes relevant only when the modification goes far beyond normal cosmetic styling.

Do I Need TÜV or ABE?

No.

TÜV and ABE are mainly associated with the German vehicle modification and approval system.

They are not standard UK requirements for a conventional body kit fitted to an already registered vehicle.

For a UK owner, the more relevant questions are:

• Is the part securely fitted?
• Does it create a dangerous projection?
• Does it affect steering or braking?
• Does it obstruct lights or the registration plate?
• Has the vehicle’s structure been altered?

Do I Need a New MOT After Installing a Body Kit?

No special MOT is automatically required.

A normal body kit does not create a separate “body-kit MOT approval” process.

The vehicle continues on its normal MOT schedule.

At the next MOT, the fitted body kit becomes part of the vehicle being inspected.

DVSA will look at issues such as:

• security
• damage
• risk of detachment
• dangerous edges
• interference with other vehicle systems. (gov.uk)

So the normal process is:

Install the body kit → check it is safe → continue using the vehicle → attend the normal MOT when due.

How Much Does It Cost?

For an ordinary cosmetic body kit, there is normally no government approval cost.

The current statutory maximum MOT fee for a standard car is £54.85. (gov.uk)

That does not mean a new MOT is required after fitting a spoiler or splitter.

It is only relevant if the owner voluntarily chooses to arrange an additional MOT inspection.

For structural modifications, extra inspection, engineering or IVA costs may apply depending on the work carried out.

Do I Need to Tell My Insurance Company?

Yes.

This is separate from DVLA approval.

A modification can be road legal and still need to be declared to the insurer.

MoneyHelper advises drivers to keep insurers informed about changes to their vehicles, including modifications. (moneyhelper.org.uk)

For example, you might tell the insurer:

“I am fitting an aftermarket front lip, side skirts and rear spoiler. There are no structural changes to the chassis or monocoque.”

The insurer may then:

• record the modification
• keep the premium unchanged
• increase the premium
• charge an administration fee
• apply additional conditions

There is no standard body-kit insurance fee.

What If I Do Not Tell My Insurer?

Failing to disclose a vehicle modification can create problems with the policy or a future claim.

MoneyHelper warns that failing to provide accurate and up-to-date information may affect whether the policy remains valid or whether a claim is paid. (moneyhelper.org.uk)

The simple rule is:

DVLA: Usually does not need to be told about a normal non-structural body kit.

Insurer: Should be told about the modification.

UK Body Kit Legal Checklist

Before driving the modified vehicle, check:

Bottom Line

A conventional non-structural BYD body kit is generally legal to use on UK roads.

For normal front lips, splitters, side skirts, rear diffusers and spoilers, you will not normally need:

• TÜV
• ABE
• IVA
• a special DVLA approval
• a special post-installation MOT

There is also no general UK rule limiting a splitter or spoiler to a fixed number of centimetres of projection.

Instead, focus on five things:

1. Install every part securely.
2. Avoid dangerous edges or projections.
3. Do not interfere with steering, braking or suspension.
4. Keep lights, reflectors and number plates clear.
5. Do not alter the vehicle’s chassis or monocoque unless you are prepared to enter the structural-modification process.

For a normal cosmetic body kit, there is usually no government paperwork and no government approval fee.

If the work becomes structural, DVLA notification and supporting documents may be required.

And even when DVLA does not need to be notified, the modification should still be declared to your insurer.

Official References

DVSA — MOT Inspection Manual: Body, Structure and Attachments

Official MOT standards covering bumpers, body panels, spoilers, insecure components and unsafe body modifications.
(gov.uk)

DVLA — Making Changes to a Vehicle (INF318)

Current guidance covering structural modifications, chassis changes, monocoque modifications and supporting evidence.
(gov.uk)

DVLA — Modified Vehicle Statement V627/3

Official form used when notifying DVLA about qualifying structural modifications.
(gov.uk)

DVLA — Change Vehicle Details on a V5C

Explains which vehicle changes must be recorded with DVLA.
(gov.uk)

DVSA — Individual Vehicle Approval for Cars

Explains when IVA may apply to built, rebuilt, reconstructed or radically altered vehicles.
(gov.uk)

DVSA — IVA Exterior Projection Guidance

Technical guidance covering the 100 mm sphere, 5 mm exterior projections and 2.5 mm radius benchmark used in IVA inspections.
(gov.uk)

GOV.UK — Displaying Number Plates

Official number-plate display requirements and penalties.
(gov.uk)

GOV.UK — MOT Test Fees

Current statutory maximum MOT charges.
(gov.uk)

MoneyHelper — Car Insurance: What You Need to Know

Government-backed guidance covering the disclosure of vehicle modifications to insurers.
(moneyhelper.org.uk)

Ready to check a BYD body kit for your car? Browse our BYD exterior accessories collection for body kits, lips, grilles and spoilers. If you need a specific fitment or cannot find the part you want, contact us with your model, year and VIN — we provide fitment and sourcing support.