It's quite east actually! get a 4mm ish flat ended screw driver and poke it up the hole in the bottom of the mirror casing, you should feel a series of notches that the blade will push into. Give the screw driver a quick push to either the left or right depending which side mirror your working on and the mirror glass un clips. Easy !
No pics as i've lost my camera somewhere! need to find it before Brooklands though






