Replaced the rear passenger door lock module as I thought that's why the vanity light wasn't working.
Turned out that wasn't the issue. Light still not working.
Found out that the screw holding in the door lock cylinder (arrowed below), is only supposed to be
turned 12 revolutions.
Not removed.
If you remove it all the way, the gold mounting bracket (just visible on the right)) falls out.
Whole thing then needs pulled apart! Ask me how I know.
However, I learnt that (part of) our cars are actually made in ENGLAND! (arrowed)