Bathroom Tile

I'm going to offer a suggestion (not that you need it) but often and even more so when you're laying tiles that need individual trimming as these do I find it easier to 'do the floor' off-site and with this I would cut a piece of mount board to room size and tile that!........You probably already knew that!

Big benefit is it can lay loose giving you wiring access to the ceiling below..........you probably knew that too so I'll just leave quietly!.....BYE!

@MikeUK, ugh, I wish I knew that before. I glued it straight to the floor. I've been wondering about how you deal with wires from lights that go bad. I guess that is why so many are moving to battery operated led lights.