My brand new Mercedes-Benz E300 has suffered a number of faults with the hybrid system, braking down within three days of delivery. The car has been at the dealer for three weeks and I have been told it requires a new hybrid battery pack (£9000 pounds + labour).

Incidentally, a hybrid fault results in the car immediately shutting down (just like you have taken the key out) which is very unsettling at speed. I am understandably not keen to have the car back in case the attempted fix doesn't resolve the issue.

I have put in a request to reject the car, as nobody in their right mind would consider that to be of satisfactory quality, but I would like to be confident that the law is with me on this one. Can you offer any advice?