I know that bathroom fans seem to be one of the most oft-covered
topics (why isn't it in the FAQ?!); but unfortunately I can't seem to
find an answer to my specific query via google...

I'm installing a simple bathroom extractor fan (Screwfix 15927); I'd
like to wire it through a 2-gang light switch on the landing; ie, the
two switches would control the bathroom light and fan completely
independently. There's no timer, humidistat, or anything else; just
straightforward on-off.

Is this permitted under the regs? I can't see why not, but the fan
instructions state that I can only wire it independently using a
pull-cord switch, or wire it in parallel with the bathroom light.

And does the fan still need to be wired through a double-pole
isolation switch, despite not being wired to the light? Can I just use
a double-pole FCU like Screwfix 16437?

Thanks
David