Performance by cohort

3 year bands · 1,410 tests

Pass rate climbs 3.0 points across the cohorts — newer GT 125i examples clear the test more reliably than the early cars.

Pre-2018 cohort 164

Pass

84.8%

Fail

9.2%

PRS

6.1%

Avg mileage at test

4,521 mi

2018–2020 cohort 969

Pass

88.3%

Fail

8.4%

PRS

3.1%

Avg mileage at test

3,715 mi

2021+ cohort 277

Pass

87.7%

Fail

6.9%

PRS

5.4%

Avg mileage at test

3,700 mi

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

The picture

Gt 125i: above-average pass rates, with caveats

Across 859 MOT tests, the Gt 125i returns 83.7% first-time pass — above the UK fleet average. The single most-logged Major fail is stiff steering bearings. A non-functioning shock absorber and a binding brake round out the top three. Average tested mileage sits at 3,345, 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.

Top ten reasons for rejection.

Filter failures:

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

01

Steering head bearings excessively stiff, notchy, or with excessive wear or play

29 occurrences · 2.1% of tests
02

Tyre tread depth not in accordance with the requirements

21 occurrences · 1.5% of tests
03

Significant brake effort recorded with no brake applied indicating a binding brake

9 occurrences · 0.6% of tests
04

A headlamp missing, inoperative or more than ½ not functioning in the case of LED

8 occurrences · 0.6% of tests
05

A wheel bearing with excessive play

7 occurrences · 0.5% of tests
06

A direction indicator lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning

6 occurrences · 0.4% of tests
07

Brake lining or pad worn below 1.0mm

5 occurrences · 0.4% of tests
08

Significant brake effort recorded with no brake applied indicating a binding brake

5 occurrences · 0.4% of tests
09

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

5 occurrences · 0.4% of tests
10

A headlamp missing, inoperative or more than ½ not functioning in the case of LED

5 occurrences · 0.4% 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 3 failures

£160–£365

If every one of this GT 125i'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 →

Try the calculator

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 3.6-point gap between bands means the year you buy Royal Alloy GT 125i has a real effect on what turns up at the garage.

Best band to buy

88.3%

2018–2020 registration

the 2018–2020 band climbs to 88.3% — a 3.6-point improvement. Failures here are mostly wear items: excessively stiff or notchy, tread depth is below minimum requirements of 1.0mm — the structural issues that drag down older examples don't appear in the top-10 for this band. The stricter post-2018 MOT test rules meant manufacturers had to tighten up emissions and electrical checks, but this band still shows far fewer major failures on suspension and bodywork than the older fleet.

Band to be cautious about

84.8%

Pre-2018 registration

On the older band (pre-2018), the data shows a 84.8% pass rate against a fleet average of 88.3% on the newer band. The main culprits logged at test: excessively stiff or notchy, excessively binding, and light intensity obviously reduced. Average mileage on test for this band is 4,521 miles — high-mileage wear items are a recurring theme.

Best band to buy: 2018-2020 (88.3% first-time pass). Worst band to avoid: pre-2018 (84.8% pass). That's a 3.6-point spread across 164 older tests and 969 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

Digital tyre-tread depth gauge

Five quid for a gauge beats £150 for a retest. UK MOT minimum is 1.6mm — most testers fail anything below 2mm to be safe.

Search Amazon UK

Item 02 · 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.

Get a quote →

Buying or keeping a GT 125i?

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 a GT 125i 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.