Summary:

I recently got my car serviced and very soon afterwards my car started to break down. The garage have examined the car and are not taking responsibility for the issue, and I am being faced with a hefty repair bill. I would like some advice on how likely it is that the garage that performed the service is at fault, and what my best course of action is from here.

Full detail:

I recently got my car serviced and the next day after driving away from the garage (c.15 miles of driving) my car began to experience difficulties starting up. After a couple of attempts I got it started again and was able to complete my journey, however from the next day onwards the car would not start at all.

A fairly small amount of oil was also leaking from under the bonnet onto the driveway - around a small cupful if I had to estimate. During the service the oil was changed, along with replacement of the cabin air filter and brake fluid. The service had also identified various fault codes which the garage cleared.

The car was recovered to the garage for diagnosis of the issue. After 16 days of having the car and looking at it on and off, the garage came to the conclusion that a fuel injector was stuck open, which had flooded the engine and exhaust system with diesel. As a result, the injector needs to be replaced, an exhaust regeneration performed to clean it and a new battery, leading to a bill of almost £1000 including £400 just for the replacement injector.

The car is 9 years old and has 110k miles on the clock, so it's not unreasonable that an injector would fail, but the timing makes me feel uncomfortable given the issues began almost immediately after the service.

The garage are not taking any responsibility, saying that "it's just one of those things" and bad timing. They say that while the injectors were not inspected during the service, a visual inspection of them like the one recommended in the dealer's maintenance schedule would not have identified the issue anyway.

They say that while the other injectors have not been tested, they are currently working, but to test them they would need to be sent away resulting in further time and expense. I'm not sure about this because an internet search suggests there are various ways to test an injector.

They say that no more oil is leaking, that any excess oil on the car's undercarriage would be old oil that was washed out of the engine during the service oil change and took time to drip down from the engine.

While it'll be hard to prove without the vehicle being independently inspected, is it likely that the garage is correct on all of the above points, and it is a very unfortunate coincidence, or is anything dodgy going on?