Realised there are no good quick DIYs for this job on the interwebs. All I can find suggest it's a pita and a difficult job requiring full door trim disassembly. That is not the case. Here is my 5 min DIY per side!
1) remover cover from inside the door. It just pops out.
2) remove the mirror. Be careful not to damage it
3) remove connectors. I marked the inside one with red tape incase there is a difference how the attach. Assume not but like to be precise. They are corroded usually so use needle nose pliers.
4)
Remove motor mounts. 3 small screws.
5) unplug by spreading apart two tabs and piling away gently
6) unscrew the main bolt that holds the housing. And pull it away half way
7) unscrew 2 screws that hold the small bracket inside the housing.
if only removing the outer casing, attach the housing back to its original position. Make sure rubber seal sits properly.
9) use a screwdriver and push on the inner bracket pushing it away from the mounting holes. It will move about 1-2cm.
10) unscrew 4 crews from inner housing.
11) now gently but firmly pull the hole assembly towards the rear of the car.. It sits pretty tight but will come off fairly easy! Apply firm but gently pressure, don't yank it.
12) pull the wires through the housings both inner and outer.
13)
And here you have it. 2 housings removed in around 10min. Ready for what ever you have planed:) or simply to replace..
Please move to sticky section if it useful to anyone.
Always worth checking the FAQ sticky at the top of the page to see if the DIY project has been covered before. If not, get it done and then PhilT can be add it to the FAQ post.