The shower control version   and the wash basin and kitchen version
The long lever part unscrews which then allows you pull the top part off, or adjust the top so that the hole in the top lines up with internal release button with a small screwdriver.
You should then see a screw that you take out and the micro switch assembly can be removed.
It’s a bit tight for space in there but hopefully you can get enough slack in the wiring for you to solder the wires back together and put insulator tape around.   On many occasions it the wire has failed from the amount of twisting that operating it causes .
You may be lucky and find its just a terminal worked loose an needs adjustment.
I repaired mine twice before getting a new microswitch (ebay) but getting to the wiring underneath can be a nightmare.