Richard,
I can understand your frustration.
When mine played up I said to my mechanic keep it until you fix it.
As I didn't have a diagnostics plug on the car, he had it for a week tracing the fault. I had a few wiring issues, which resulted him spending a couple of hours a day (ling enough upside down in the cockpit) fixing it.
Without a diagnostics plug discovering the problem was a lot harder, but in the end he got there.
The car has never failed to start since
