Hey Aussie! We have HyperVent matting underneath our mattress and it works wonders. It manages to wick away moisture even when we're at sea or living in a foggy harbor.
Before living on a boat I lived in a trailer
in the redwoods (mold central) - and I learned a couple of things...
- clean with white vinegar if you don't want to use bleach or toxic stuff. you can mix it with water
or use it straight-up. kills mold.
- running a dehumidifier works great of course
- for passive dehumidification, these babies work
pretty darn well