I haven't used them personally but the Westover group who have Abarth and Fiat franchises have a very good bodyshop I am told, located in Poole, (they repaired Heidi's Funk White 500 without all the hassle that LovesHandBags had to go through). Their smart repair service includes alloy wheels and they have and 0800 number to get a free estimate. Why not give them a ring?
http://www.westovergroup.co.uk/aftersales/view/936/smart-repairs
I'll give them a call - I did already talk to a Fiat dealer but maybe Westover might be better.
Thanks