Gaz they advised me to adjust my low jet on the carb, I went to the field today and put everything together, started the motor then it stopped. To cut a long story short we found the plug had failed just completely broke down which I found very bizarre. So off to halfords for a new plug, all seems well now, I went for a short flight and the motor behaved itself, although I am a bit twitchy as I cant understand why or what killed the plug.