Wiring a fan and light in bathroom with separate switches

I would like to put switches on my light and fan in the bathroom. At present there are 2 isolators. The light one is fine–it has a twin and earth to the light so I guess that’s straight forward to bring the live to the intended switch and a twin and earth from the new switch to the light.

The fan isolator is 3 pole and has two 3 core cables connected, 2 cables are coloured grey and are connected to the Neutral connections one above the other we then have 2 black cores connected to L2 AND L2 (ONE Above the other) so when the isolator is switched on they are connected to each other as is the Blue marked cables, the two brown cores are not connected to anything they are just taped up. Is that any help at all.

The bathroom has a motion sensor fitted in the ceiling. At the moment I have no ladders to reach that item but I hope I have given enough info for now. I cannot put the pic I took as its too large.