Vivaro wing mirror replacement

[Zuckerman]

How easy is it to replace the entire electric wing mirror unit on a mk1 vivaro?

Garage have quoted £375 but you can get secondhand units for 40 quid - is it easy to fit, including wires for powered adjustment/heating etc? (The heating doesn't work anyway)

Cheers for any tips

[E-bmw]

Don't know on the Vivaro, but most are just a couple of screws behind an internal trim panel & a plug for the electrics.