My car - a Peugeot 307 - was running perfectly and as its a 2.0-litre diesel I put it in for a cam belt change at 91,000 miles. The car came back and didn't start, so I took it back to the garage. They kept it for another week then said a fuel line had been dislodged and an injector was blocked.

I asked them to sort it and when I got it back after a day, the engine was knocking. They've had it for another week and are now saying the the bearings in the rocker arms are gone and one of the rocker arms has snapped. I believe this is all due to them not replacing the cam belt properly. They deny this - so I am not sure what my next step is?