I've spent a lot of time abroad, those things are day to day necessities in many countries. In Europe, the New World and Australia things are pretty consistent, but in Asia it's a bit of a mess so universal outlets are the norm and local (well, usually American, which is clearly better than the European, even though the local Asian electricity doesn't usually match American) male to universal female powerboards are everywhere.
As for the female outlets... crap, I actually didn't think about that, I think I sort of figured you were using it along with compatible equipment. That part actually would be a hassle. In my younger days I'd have rewired it myself, I can rewire it as safely as a factory wired unit (possibly better depending on the factory quality) but these days I'd probably just not use it. If ever there was a fire, even for another reason, having a home-wired thermostat is possibly going to leave you liable/void insurance. Piggy backing too many adapters and powerboards etc off each other is also a recipe for disaster. I wish I had a picture of the incredible mess of double adapters and power boards all connecting to one single outlet in the herp room I had about 18 years ago, it was the most insane working mess of such things I've ever seen. The initial cable coming out of the outlet was warm to the touch, it's amazing it never blew a fuse (we did still use actual fuses back then).
Realistically, going from Australian outlet to UK thermostat back to Australian heating equipment is going to require two levels of adapting, so outlet to adapter (1) to thermostat (2) to adapter (3) to heating element (4) is four loose connections between five individual conducting modules. Your other option is to rewire it which is technically illegal (unless you're an electrician) or to get an electrician to rewire it which will be more expensive than a new thermostat, and depending on your skill you could rewire it which may be dangerous or legally problematic.
One good thing about UK plugs is that they're ridiculously overengineered, making them very secure, so if you do go to the hassle of the universal adaptors it'll be much better than if you were using the hideous European one or even the American one. The Australian male plug also fits pretty securely into a universal female outlet.
Honestly though, I'd just get another thermostat.
Oh, another option is to use a universal powerboard and UK heating equipment.