Thanks - useful comments and ideas. All three solutions easier than mine to lesser or greater extent!
Will suggest a remote humidistat to my client. Cheers.
Out of interest, was my original solution safe / to the regs? Just out of interest.
Gents,
I want an over-run extractor fan to come on when the shower pull cord is pulled on, then run on for a timed period after the shower pull cord is 'pulled off' (snigger snigger).
My solution:
The shower circuit is currently run in 10mm t&e. Take a 10mm t&e feed off the permanent...