Fez it will be what Shinysideup has said. It plugs into a small sensor that is on the underside of the airbox lip, right next to the frame at the right hand side of the bike.
Yeh as soon as I read it I realised, dont remember fitting it, stupid really as I have stripped it twice before and never had a problem, my head must have been somewhere else that day
Have been at work all week and not had chance to strip the bike down yet, as soon as I do I will give you an update
Yeh, it was the little vacuum hose on the bottom of the airbox, running perfect again now. Only needed to lift the tank and slip it on, was a relief as I was thinking I might have to strip it all again