GTR wing mirror attachment help

[renmure]

Can anyone tell me, in really simple terms, how the wing mirrors attach to the doors on the GTR please.
Idiot proof schematics, diagrams, pretty pictures etc would be particularly welcome

My car was in a workshop getting a new windscreen sun strip fitted and when I got home I noticed that some numptie (may have been me and I hadn't noticed before but I doubt it) has likely shut the drivers door with a bit of a slam and there is a small crack on the stem of the mirror near where it joins the door.

Just really considering what my options are at the moment.

Thanks.
Jim