Re: Radiator Fan won't come on ???
the part is exclusive to the 145/146, try breakers or ebay, just make sure you get one for aircon if you have it as the non aircon ones are different. Otherwise may well be the dealer.
The thermostat does not control the fan, the temp sensor sitting in it does, I suspect the garage put the old sensor in to the new stat, not normally a problem to be fair. Does seem a bit of a coincedence, but its difficult to know what they could have done to break it TBH.