Just had an update.
Apparently on the inlet there is a valve that opens when the cam is at is highest position ?? Anyway, apparently mine is not closing again and is remaning open. They've tried one from another car and it clears the fault so a new one is being fitted tomorrow.
I'll try and get more useful info tomorrow as between the phone call and typing this my brain seems to have muddled up everything he just said !
Daz