It's pretty easy.
First, glass off. Angle mirror to the sky then push top to angle some more.
There is a ring that locks the glass to the shell.
Medium / small flat head screw driver in the gap you now have at the bottom of the glass. Insert parallel and butt up to glass. There's a small notch the tip inserts into. Now you need to rotate to unlock the glass. More of a lateral movement as the amount of travel to unlock is small. Can't remember if it twists towards the car or other way though. Glass off.
Then a few torx bolts to get the shell off.
Done
You might need to get the plastic panel on the underside off to remove the shell. This is a pig to put on I'm situ.
Other option is to remove entire assembly. So door panel off disconnect power to mirror the undo bolts behind tweeter.
