Guys, thanks for the info. Rick heres (hopefuly) a top and side shot of my mirror. It is 12 3/4" from the front of the door to the front of the mirror base measured along the top crease of the door.
[Blocked Image: http://i42.tinypic.com/f3yn4m.jpg]
[Blocked Image: http://i39.tinypic.com/x1caav.jpg]
The window opens ok.
Is your mirror glass tinted? as mine is
Mark
Ps I think its an original as its nicely patinated and I have 2 speed wipers and multi speed heater fan which comprised the visibility pack. Fred correct any of this if I am wrong.