Thank you Bongonauts for your replies but my mechanic discovered the problem today! The cat converter was blocked. So I am now flying and able to continue with my road-trip.
Happy travels Patzy :

Its a 2 litre petrol.

Am stuck in a garage hundreds of miles from home in Northern Ireland and my mechanic is stumped by the problem. The water temp gauge now fixed and OK. Compression check made all around165psi. Engine ticks over fine but behaves like mainn jet blocked on a carbed engine. Unable to get the flash codes ...