Recently my sister was driving her nearly-new Volkswagen Passat on a motorway and was terrified when the wipers failed. It has automatic wipers. It was repaired for £300 but has now failed again and, when we complained, were told that £200 of the repair cost was for fault location.

I am outraged by this. They failed to repair the fault and they don't care. This leaves the car in very dangerous state. My sister does not like hassle and is thinking of bringing car to an electronic specialist to have it repaired. Surely this is unacceptable from a main dealer who claims to have a quality approach. And to pay £200 for fault-finding to someone who can't locate a fault is crazy. What should we do?