Thanks for all the help guys.
Took me four hours in the end, bumper wouldn't come off as my torx bit snapped in the fixing (!!) so i managed to get at the air con rad bolts by prising off the lower grill. The couple of 6mm bolts at the bottom were an issue,i'm afraid some butchery was required.
Take off the pipe from the air box to the MAF, take the fan off with the rad in the car, disconnect the rad hoses at the engine end and wiggle it out. Taking the airbox out might have been easier (give a bit more room for the bottom off side fan screw) but i couldn't see where the bottom fixings are.
One of the tags had actually broken off the resister thingys base bit, but its copper so i was able to solder a wire to it then clamp the other end of the wire to the resister with a bit of choccy block. The resister must be made of some funny metal as ordinary multicore solder won't stick to it.
Anyhow, it appears to be working at the moment and its easy enough to change in the future! Good tip from David to bypass it though.
Getting it all back together was far easier than taking it apart!
I replaced all the Alfa hose clips with jubille clips.