Performance by cohort

3 year bands · 2,550 tests

Pass rate drops 3.1 points across the cohorts — recent Unclassified examples are doing worse than the early cars at the same tested age.

Pre-2018 cohort 1,584

Pass

88.4%

Fail

8.7%

PRS

2.0%

Avg mileage at test

13,477 mi

2018–2020 cohort 756

Pass

90.1%

Fail

8.9%

PRS

0.9%

Avg mileage at test

5,468 mi

2021+ cohort 210

Pass

85.2%

Fail

12.9%

PRS

0.9%

Avg mileage at test

4,852 mi

Cohort = vehicle's first-registration year band. Same model, different generations of build.

The picture

Unclassified: a strong MOT record by UK norms

Across 1,230 MOT tests, the Unclassified returns 87.9% first-time pass — comfortably ahead of the UK fleet average. The single most-logged Major fail is a torn suspension dust cover. Emissions levels exceed the manufacturer's specified limits and windscreen damage round out the top three. Average tested mileage sits at 10,188, which is the lens to read those failure rankings through. If you own one and the next test is close, the ranked list below is a sensible pre-test checklist.

ABI Insurance Group

Group 28–42

Above average — worth comparing quotes before buying. Lower groups cost less to insure; UK fleet average is around Group 22.

Source: ABI Group Rating Panel · administered by Thatcham Research · groups cover standard variants; performance trims may sit higher. Browse all insurance groups →

28–42

out of 50

Compare quotes →

Top ten reasons for rejection.

Filter failures:

Hide wear items to see the model's real defects.

01

Lambda coefficient outside the default limits or the range specified by the manufacturer

31 occurrences · 1.2% of tests
02

Emissions levels exceed the manufacturer's specified limits

28 occurrences · 1.1% of tests
03

Emissions levels exceed default limits

25 occurrences · 1.0% of tests
04

Steering rack gaiter or ball joint dust cover damaged or deteriorated

17 occurrences · 0.7% of tests
05

The aim of a headlamp is not within limits laid down in the requirements

17 occurrences · 0.7% of tests
06

A suspension joint dust cover severely deteriorated

16 occurrences · 0.6% of tests
07

Emissions levels exceed default limits

16 occurrences · 0.6% of tests
08

Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view

15 occurrences · 0.6% of tests
09

Number plate does not conform to the specified requirements

14 occurrences · 0.5% of tests
10

A reversing lamp inoperative

14 occurrences · 0.5% of tests

Counts cover Major and Dangerous defects logged at test. Advisory items excluded so this shows why a car was rejected, not just what the tester flagged in passing.

Worst-case fix budget · top 2 failures

£90–£320

If every one of this Unclassified's most-logged Major fails hit at the same MOT, that's the real-world UK garage range. Reality is usually one or two items, not all of them. Open the estimator →

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Build your own retest budget.

Year-band analysis

Best year to buy. Worst to avoid.

First-time MOT pass rate split by registration band. A 4.8-point gap between bands means the year you buy Caterham Unclassified has a real effect on what turns up at the garage.

Best band to buy

90.1%

2018–2020 registration

the 2018–2020 band climbs to 90.1% — a 4.8-point improvement. Failures here are mostly wear items: lambda reading after 2nd fast idle outside…, tread depth below requirements of 1.6mm — the structural issues that drag down older examples don't appear in the top-10 for this band.

Band to be cautious about

85.2%

2021+ registration

On the 2021-on band, the data shows a 85.2% pass rate against a fleet average of 90.1% on the newer band. The main culprits logged at test: does not conform to the specified requirements, lambda reading after 2nd fast idle outside…, and carbon monoxide content at idle exceeds manufacturer's…. Average mileage on test for this band is 4,852 miles — high-mileage wear items are a recurring theme.

Best band to buy: 2018-2020 (90.1% first-time pass). Worst band to avoid: 2021+ (85.2% pass). That's a 4.8-point spread across 210 older tests and 756 newer ones — year of build makes a material difference on this model.

Year-spread leaderboard →

Tools that pre-empt a retest.

Picked against this car's top failure patterns. Affiliate links to Amazon UK — we earn a small cut at no cost to you. Disclosed up-front, doesn't shape the data.

Item 01 · Amazon UK

Headlight restoration kit

Yellowed lenses fail the light-output test. A restoration kit lifts the haze in an afternoon for £20.

Search Amazon UK

My Motor World · affiliate

Parts & supplies for this fix

Affiliate links — small commission, no extra cost to you.

Denso

Denso W14E Spark Plug (Single)

£1.09

View at My Motor World →

Denso

Denso W16EX-U Spark Plug (Single)

£1.09

View at My Motor World →

Denso

Denso W16FSR Spark Plug (Single)

£1.09

View at My Motor World →

Denso

Denso W9LM-US Spark Plug (Single)

£1.09

View at My Motor World →

Click Mechanic · affiliate

Book a mobile mechanic

Affiliate links — small commission, no extra cost to you.

Mobile mechanic · UK-wide

Book a mechanic at your door.

Fixed-price quotes upfront. No garage needed. Click Mechanic sends a vetted local mechanic to you — home, work, or roadside.

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Buying or keeping an Unclassified?

Use the failure ranking as a pre-test checklist or a haggling lever. Treat the headline pass rate as a fleet-wide trend, not a guarantee on any individual car.

If you own an Unclassified and your last MOT looked nothing like the ranked failures above, that's normal — individual cars vary widely. The ranking shows the patterns testers flag most often across the country.