You surprize me Brian, and what if there is no RCD protection (I still would not). The OP has not mentioned that, would you still fit a switch inside the bathroom."
Not a question that I can answer, since I've been fitting RCDs to ALL domestic circuits since they became available. My customers have been given no choice in the matter.
The regs, however, have always allowed wall switches to be fitted in bathrooms, subject to certain distance based conditions.
I posted on here once before about the hilarious sight of the overweight SWEB head honcho, balancing on the edge of a bath, desperately trying to prove that an immersion heater switch was within reach.