Mystery shop finds UK garages overcharging for simple sensor repairs
An undercover investigation from German diagnostics specialist Carly has found that British drivers could be charged up to five-times the cost for a simple sensor repair.
Carly carried out a mystery shop to assess whether UK garages charge consistently for the same repair – and to gauge public confidence in the process.
Using the same Seat Ibiza with a known oxygen sensor fault, the investigation uncovered significant price disparities, with quotes reaching as much as £672, depending on the garage.
The mystery shop investigation, conducted by Carly across 10 UK garages spanning independent and main dealer networks, found that while every site correctly diagnosed the issue (P003100), many quoted significantly inflated prices.
While the garages themselves are unable to be identified, Carly said that a garage in Leeds (national chain) quoted £672 to replace both oxygen sensors, a main dealer in Stoke-on-Trent quoted £618 for oxygen sensor replacement and another main dealer, this time in Sunderland, quoted £328 for oxygen sensor replacement, all well over the £110 expected standard.
Beyond inflated pricing, Carly said the investigation revealed a pattern of unnecessary upselling. Four of the 10 garages recommended additional repairs or servicing that were unrelated to the known fault, including brake replacements, spark plugs, air-conditioning servicing, and duplicate diagnostics.
In some cases, these add-ons would have added between £400 and £950 to the total bill.
Supporting the findings, a OnePoll survey of 2,000 UK-based motorists revealed that 52 per cent either suspect or are unsure if they have been overcharged in the past five years, with many admitting they feel powerless when faced with repair bills.
Forty per cent also said additional work is often recommended without a clear explanation.