Hi
Thank you for your reply, I haven't forgotten about it just have been very busy. I don't want to ruin it by cutting the wires instead, If I find enough time, I'll strip the mirror and I'll try to machine the missing (damaged part). My mirror has been hit by the previous owner which, as you've said earlier, may explain its behaviour. Can you think of a website/or do you have access to the driver's side door with mirror assembly diagram/schematics/pdf or something similar ? I've never done that so I'd like to work methodically by knowing what I'm doing.
As for the second part of your message, I'll let you know if I find anything. £400 for a mirror is a ridiculous amount of money!
Cheers