StevenRB45 is up there in the Newcastle area so may be able to advise on reliable garages? However, as mentioned above, the engine is a very common one found not only in Fiat branded vehicles and many garages will be very familiar with it. It's not a particularly difficult belt to do either but make sure they do a complete kit, including the water pump, because the water pump is part of the drive train so if it fails it may well cause the belt to either skip teeth or come off altogether. A 2008 1.2 engine should be non interference so, even if the belt does skip teeth or actually break, all that will happen is the engine will stop. It won't cause internal damage but might be very inconvenient or dangerous depending on where you are at the time! If memory serves me correctly the recommended change interval on these is 5 years or 70,000 miles (whichever comes first) but it's very rare to hear of one failing even when neglected - which I'm not suggesting is a good idea! Our 2010 1.2 Panda had obviously not had one done when we bought it at around 60,000 miles 8 years old and neither had my boy's Punto (1.4 but an almost identical engine). Our Panda had a very slightly noisy water pump bearing but the belt, whilst showing it's age, would have gone on for some time yet. The boy's Punto probably didn't need doing but I changed it as a precaution (newly bought car with little service history) but also because it's the later VVT engine so is an interference type.
Going forward I tend to be conservative about belt change intervals so tend to watch for when either exceeds 4 years or 50,000 miles and with neither car doing high annual mileages that means I'm typically catching them when they go over the 4 years and then looking for a nice dry warm day to do the job - could be 6 months or more down the line from when the 4 years is exceeded.
OOPs! Yours is a 500 isn't it? Sorry, I'm very Panda/Punto orientated. The 500 was always interference I think (jrk will know for sure) so better not to ignore recommended change info.