Feedback on the mirror.
Be careful when you unclip the tweeter panel, as you can very easily crack it. I started at the top and worked my way downwards.
As mentioned above there are 3 screws holding the mirror to the door. Two of them easily spotted (although one is behind and to the left bottom). The third one, however, is behind the rubber strip that run along the top of the door. (Red circle)This needs to be slowly squeezed off with a small nose pliers, as the rubber can be damaged with a screwdriver (yes I did). Once you sorted them the mirror can be removed, just be careful, it got a rubber like backing that can be fused to the body if the car is old.
The problem was that the mirror was bump as Deckchair5 suspected and one of the bottom screws (actually copper nuts with a screw pattern on them) pulled out of its recess, and cracked the plastic around it. But it is sorted now.
Hope this feedback will help.
G