The light switch in my downstairs toilet is just a normal rocker type.
ISTM this is somewhat dangerous due to the proximity of basin & WC, so
I'm looking for a safer solution. Idealy I'd put a pull switch on the
ceiling, but access from above is a little tricky. I could chase the
cable up the wall, or put it outside the door, but a simple solution
would be to replace the current switch with a waterproof one.

Any suggestions for an appropriate device, and would it satisfy building
regs anyway?

Peter.