Ok I'll do a load test on the battery. Was chatting to a mechanic mate last night and he suggested the same thing.

Ive tried to eliminate the earths by putting a jump lead between the battery and various points on the body/engine and it hasn't made a difference?

I think it's got to be a relay sticking or battery voltage causing problems somewhere as its the only thing that explains why it goes by jumping it.

Its the fact it cranks over normally that i don't understand?