At the moment i'm using Brights Garage in Evesham who used to be a main Fait Agent and then was stripped of its status ages ago. And is now just an official "Fiat Specialist". Been owned by the same guys for yonks. He has some lovely cars there including a whole collection of Fiat 500's and he has a gorgeous 85 ELX in metallic orange.
Hlyton were useless. Went in to order a speedo for the punto and couldn't even find the part number and then they said the delivery would take upto four weeks anyway. There not always bad though i'm sure.
Brights know everything on Fiats and don't charge dealership prices either.