Copied here from the general forum ...
Finally got around to looking at these.- the tilt function when reversing worked well when I bought the car but over time it has reduced to the point where it just twitched when moving into reverse.
I planned to have a look at it months ago but just never got round to doing it.
I done it today and took pictures of each step. It took half an hour for the first mirror and 20 minutes for the second so not a time consuming job. I needed to replace two worn plastic motor worm gear cogs which had partly stripped and I gave the mirrors a very good clean inside and out. Re-greased and oiled. They had accumulated a lot of dirt over the years and I don't think anyone had been in them since it rolled off the production line so it was a well worthwhile job.
They are now working spot on and are holding their memory positions when starting the car. I could not get them to stop working after testing them for about 10 minutes so am happy and confident they are now fixed.
I think the winter has a big effect on them when they are frozen up - they will automatically try to set themselves to the user position and also will try to move when reversing which puts a strain on the motors making them skip and strip teeth.
Anyway - what I have done below worked for me - I have two good motor units left spare which I sourced which you can use the plastic work gear from or the units themselves if anyone does this and finds they need them.
Pictures below are in sequence marked from picture 1 to 14. I have never managed to fit them into a post with instructions against them so the instruction is on the picture itself.