2005 A8 Folding Mirror problem

[the-gofer]

My driver's side door mirror is stuck in the up position (although I can twist it down on the impact protection springs to somewhere close to a driving position). The switch activates and the passenger mirror will go up and down. The mirror glass is also positionable in the driver mirror. I have taken the case off and checked that the connections and when the mirror fold switch is toggled back and forth 12v and -12v are seen across the motor respectively for a few seconds but no whine from the motor itself.

My question's are:
1) Is there a known problem where the motor drive can just jam - badly meshed cogs etc. Or is the motor likely to be just dead
2) How the hell do you remove the motor? I tried bashing, undoing all the screws, unclipping everything I could see - this thing is built like a tank!
3) If the answer to 1) is "dead", is there anyone I can go to get a decent replacement. Bear in mind I have seen another forum somewhere that a dealer replacement is ~£400!

To be honest, I don't really use them very much because they only save a couple of cms in overall width, so if there is a fix whereby I can force the motor back round to the correct position that'll do me for now.

Cheers in advance,
Gordon