It's also worth saying that sometimes the boxes end up being quite deep
because of mounting position and depth of tiles. Longer screws for
the wiring accessories are available if that happens.

And obviously that this is only acceptable if the wall material is
non-combustible. Obviously, tiles and adhesive are fire resistant, so a 10mm
gap between accessory and box is fine. I'd want to be a lot more careful if
the surrounding material is wood.

Christian.