(T) Reversing sensors wiring/bumper removal

nip to nearest dealer & get a tech to show you where screws are

Been to local fiat today. They've never removed one so still in the dark. Am going to remove wheels now and see where I get.

I dont remove wheels, just use 'dumpy' screwdriver.

Well I've sort of done it. Bumper off, as you say 3 screws and another holding the bumper to the shell. 4 bolt screws underneath (black bumper) and another contacting black to colour coded centrally above the number plate and reached at from inside the bumber (bit fiddlly), put it back together although made pigs ear of reattaching the black under bumper as I don't seem to be able to fasten it correctly around the reverse/fog lamp. Ran out of time and light so it is attached securely and I'll have another go tomorrow when I get home from work. If you know an easy (easier) way of attaching it correctly would appreciate it and thanks for your help to date.
Steve