[M Fifty]

Okay, so mixed results.

Fitting - apart from the effort of lifting seats in and out slowly and carefully - was plug and play.

Modules were swapped from old to new seats, and the battery was disconnected for the whole process on unplugging, swapping and plugging back in.

But the airbag lights are on, and the side bolsters don't work (although the lumbar support does)

Everything else works as before.

Edit: Maybe I should have swapped the seatbelt tensioners as well...

For reference:
Old seats: M2 LCI electric seats with side bolster adjustment
New seats: M2C electric seats with side bolster and lumbar adjustment