I have a 2009 S2 Exige S and I’m planning (or was) to replace the stock mirrors with some craftsquare or raceview items. Problem is my car appears to have a plate or possibly the window runner over the bottom bolt. How on earth are you meant to remove the mirrors in such cases?
Hello all BTW, I’m new here 
Changed my mirrors on my 58 plate without any problems other than dropping a fixing inside the door
this may help
How did you drop the bar or did you just drop the bolt?
Lowered the window and removed the 3 fixing bolts but manage to drop one inside the door then spent an hour trying to fish it out
Ah ok, doesn’t help me as the bottom bolt closest to the window is covered.
There should be 3 bolts to undo to take a wing mirror off. The bolts holes will have a trim over them and also a black piece of tape over them. To undo the bolts put a bit of blue tack on your tool to undo the bolts to stop them from falling into the doors. If they do fall into your door just use a extendable magnet pen. Another way to do it which I have done on mine is use 3 Allen keys and another pair of hands if possible, then get the person to hold the Allen keys in place on all 3 bolts so there still sticking out the holes of the door once the mirror is removed. Then tape the bolt threads to the door leaving the bolts still in the door. Fitting is then easy just by pulling the tape off and screwing the bolts into the mirror wIthout ever taking them out.