They have haven't they!
Photobucket decided that they wanted £400 a year for the link, so I deleted the account.
You have to get behind the mirror glass on the inside edge, then unhook the ends of the wire clip to release it. Here are the pictures of what you are looking to get off.
Opening the window helps.
When refitting, fit the wire to the mirror glass and push it on. A small bit of lube helps. DON'T push on the edges, the mirror is not that strong. I use an old windscreen suction cut from a sat nav to hold the glass, coming off and going on.