Thanks for your reply...I have started to check the ECU also as I have read that the wiring can rub on the bodywork in the foot well and cause issues. Nothing found as yet but is being a bit of a pig to remove from it's location - a bit tight trying to slide it out of it's bracket! I am sure I read somewhere that someone replaced their throttle fly by wire assembly and this cured the problem but just trying to find where I read that. Not sure if that is my problem as when the fault originally started, I was able to drive (to a fashion!), but again, will let you know if I have any success.
Many thanks and good luck