I'm Cardiff based too and have been using ***** (yes, not Alfa) & Yapps Garages in Llanishen as they are alfa and fiat specialists.
Got the 48k service there soon after buying it and had the cam belt and tensioner changed. While it was there they found that the handbrake cables needed changing and rear brakes (pads and disks) needed doing. Eventually cost in the £700s. Not sure how much of that labour cost (approx £300) was servicing/other repairs/cam belt.
Bit disappointed this time around though as comments on 60k service recommends changing the variator (wondered why the diesel noise on start up...). Wish I'd known that changing the variator at the same time as the cam belt was a good idea.
Kind of hope that the variator lasts out until next year at least!