Hi i have been told i have to change my thermostat and temp sensor as they have both broken my car is off the road due to high emissions on the MOT........
Ignoring the leg pulling and the ones who can't read.
(although it is funny
There is some very good advise there, but lets put it all together so that you can run through it properly...
Firstly the garage obviously don't know Alfa's properly and don't have the proper kit to examine it, so don't take much notice of what they've said, as it's wrong!!
You say you've changed the MAF? Was it a new one? If so was it a BOSCH? If it was a used one is it any better? I have a good used one that I know is working fine, which (if I can find it) you could use to test yours.
FES (FiatECUScan) is a fantastic bit of kit and I'd recommend using it.
Temp going over 90 and fan not coming on sounds like your fan resistor is blown (I've got the same thing at the moment, sorting mine this afternoon) It's simple to check, just unscrew the resistor from the fan housing (top right side as you look at the engine from the front, with two wires going to it), remove it and first look at it (mine was blown to pieces!!) although you may need to check it with a resistance meter. If it is blown then simply replace it and this'll sort your temp problem out. (Hopefully)
Right you need your fault codes checking, you can do this with the free version of FES.
NickVR46 mentioned a ECU reset, and I'd second that as it does cure a lot of problems.
I think gazza82 has hit the nail on the head with his advise there.
I'll stop at that point as I think that'll sort you for now. Where abouts in Leicestershire are you? As I work in Melton mowbray and may be able to help you out if you're not too far away.
EDIT: Sorry forgot link.... ECU reset... http://www.alfaowner.com/Forum/alfa-...acle-cure.html