I can pull the junction box which feeds to the extractor fan through the hole for the ceiling light.
Likewise can pull plenty of cable through from the existing pull switch and have access via four ceiling hole lights, so could trace some cable back to a separate pull switch fairly easily...
I have a series of bathroom ceiling lights which are controlled on/off via a simple pull cord switch (10A). The extractor fan is also controlled via the same pull switch with no timer, so lights on/off and extractor on/off are together.
I would like to be able to isolate the bathroom fan...