A very good summary.Seems a lot of these posts haven't been much use to the op, but ELFI and others are on track. To re-cap ....
I don't know if you regard it as part of the discussion which hasn't helped the OP much, the other point I've been making is that it doesn't necessarily have to be a pull switch - although, with the fan in the loft. it may well be the easiest option to install.
Kind Regards, John