So i managed to get the time to get this sorted on Friday. The problem was the AFM as suspected but......... I had replaced the O2 sensor prior to this to see if that would solve the issue, and like an idiot I wired the damn thing in wrong and it was causing the ecu to think that the car was over fueling and it was cutting back on the fuel to the engine. So in trying to solve the actual problem, which was the AFM, I created another similiar problem in the O2 sensor making me think that the AFM wasn't the problem. So ya it was a bit of a cluster f**k on my own behalf. To make matters worse the mechanic reckons I've shagged the new O2 sensor by wiring it wrong as he wasn't getting a reading from it with a volt meter after wiring it properly. Chances are the one I took out was probably fine so I'm going to wire that back in for the time being as see if the fuel consumption improves, at least it was a cheap one! You live you learn I suppose!