I have bought a set of chrome mirror backs from SG petch. Getting the backs of was not difficult but the replacements will not stay on. SG Petch say they are genuine Fiat parts but but since they have not sold any others they are not aware of porblems.

The legs do not seem to be long enough to reach through the fiitting holes so do not clip in place.

Has anyone else bought these and what problems have they had if any?

All the kits i have fitted on PDI have gone on without fault, i can only think either you may have broken something when removing the old mirror back's or the new one's you have aint gen's and as such maybe ask the person you got them from for another set on exchange basis.

Maybe the fittings are different on the two different types of door mirrors available?

It's a long shot, but worth investigating.