Thanks Paul, My son took me to this particular dealer as his friend had had several cars over the years with never a complaint. The car came with 12 months MOT, 3 months warranty and had been serviced when I bought it. I contacted the main dealer (Bristol Street Motors) and they gave me a copy of the diagnostic report, they also did a visual health check - they couldn't find a problem. Spark plugs and Cam Belt have been changed. I do have a mechanic who usually looks after my cars but at the moment the dealer I bought the car from is still checking it out under warranty, even though it has now expired. The dealer's mechanic is as frustrated as I am as it just doesn't cut out when they have it in the garage, he's taken it home with him with no problems and even he's open to suggestions. I've been in touch with trading standards and on their advice written to the dealer asking for a full refund but their solicitor says I'm not entitled to it but as a gesture of good will, will continue to try and find out what is causing the problem. I've also been in touch with a solicitor and he suggested I get the RAC or AA to look at it. He also suggested I go to the small claims court, which will take at least 6 months for the case to be heard. Anyway, thanks for your suggestions, I'll pass them on to the dealer :D