A good friend makes some of the best wine that I've had, commercial and/or homemade, he doesn't use sulfites because his wife is allergic to sulfites.
You have done your research, sulfites are produced naturally during the process of making wine, and the best advice that I can give you is this:
You've been making wine without sulfites and you've been successful , you're producing wine for yourself, (the alcohol laws are different in Australia) I have no idea what the laws are for making wine in Australia, but a quick search brought me to distilling equipment, I'd say keep on making wine like you've been, maybe the only thing that I'd change is the " I am not fussy about sanitation", the better that you are with sanitation, the fewer issues you'll have overall.