I know about the zones for electrical installations within the
bathroom, but how does this relate to lights in the room below the
bathroom?

I'm shortly going to be installing flush eyeball downlighters in my
kitchen, and with the planned locations there will be one underneath
the bath, one near the toilet and one near the bathroom sink.

I do intend to make the bathroom floor above almost completely water
proof (treated boards, painted over with bitumen, plastic sheets ontop
of that with double bonded seals at the joins and then tiles on top of
all that).

What do other people do in this situation? Should I just install LV
downlighters as they would be safer? Do I need to install lights with
and IP rating, and if so, which rating?
Thanks again for any and all advice.

Seri