I agree the whole task was fairly easy but I think "a couple of
minutes" is an understatement - unless you are speaking only about the
act of removing the broken gear and installing the new one.
I did it last night and it took about 2.5 hours from start to finish.
some advice for others - the following tools helped me
1/4" hex-drive Torx bits T27, T25, T20
1/4" drive socket for 1/4" hex nut (to drive the Torx bits)
1/8" and 7/64" allen wrenches
soft blow hammer
needle nose pliers
8mm open ended wrench
16mm hex nut socket
when you get the gearbox open, look out for a small circular clip. It
fits on the end of shaft after you install the new gear - mine had come
loose and was buried in the grease.
When disconnecting the seat wiring, there are 2 identical black
connectors which could be incorrectly swapped- note the correct
positions. All the other connectors are unique.