concordnz: Get them to wire fan into your light switch & on a delay off timer. (Whenever the light is on the fan is running)
This is increasingly common & recommended practice in some areas.
Think of it like a Turbo Vehicle - which continuez to run on a delay even after you have turned the key off, locked it, & walked away.....
Try and get the 'fan' situated at the 'exit' rather directly attached to the ceiling - this will reduce 'fan noise'.
(& use insulated ducting - to further reduce 'fan noise')
That sounds annoying, especially if you have young kids who might be easy to wake. The extractor probably needs to run for 10 - 15 mins after a shower, but you don't want it to run it at all if you're say just brushing your teeth.
Manual fan controls are fine. We also have three lighting groups in our bathroom - ceiling, mirror, and LED strip lighting under the vanity.
We have a PDL timer module hooked up to ours. Press the button and it runs for a set period of time (ours is set for 10 mins) then turns off (or immediately if the button is pressed again). Has an optional mode where holding the button down will override the timer and cause it to stay on until the button is pressed again, or can also be set to turn on on the first button press, stay on until the button is pressed again then run for the set time period or until the button is pressed again. They make a similar, if more expensive module for PDL Iconic that is configured and can be controlled via Bluetooth. Keeps the fan control separate from the lights, and we have found it to be much more flexible and reliable than a traditional fan timer module (the ones that run both the lights and fan from one switch, but can also be hooked up to a seperate switch for just the fan, leaving the lights as is).