I don't know what they're like on the 172 tbh. Just checked and mine was a rear bearing for £78. The guy said he wouldn't know if it was the whole thing replacing until he looked at, which would be £2-300 I think he said.
The 1.4 was only drum brakes on the back so don't know how big a difference that makes. Worth looking on eurospares or something to see if you can buy just the bearing anyway, if you can the hopefully should just be able to replace that.