The dealer will do little to help as its nothing to do with them as such, they will no doubt just forward you to Fiat UK.
Its only them (Fiat UK) that would possibly replace the car but only after exhausting all other avenues such as sending there technicians etc etc.

I'm having similar probs with my 172 clio its been at the dealers nearly 2 months now and they have still to fix it. There changing black boxes like there going out of fashion.
I refused to accept mine back until they will give me a written guarantee that the wipers will work.