Gave the old girl a good run over the weekend, running beautifully, no sign of the problem. I can't thank you all enough for your suggestions and advice. Special thanks to Paul for coming up with the answer, you're a star mate, this has been going on since I bought the car 3 years ago!!!, I was about to give up and sell her it was driving me so mad. I'm very happy, thanks once again.

Jalacy