So I have spoken with a number of decent Australian accountancy firms and they could provide no clear guidance on the subject. I spoke with the ATO yesterday and they were very helpful, but also could not give me an answer. They said I need to submit a private ruling form and go from there.

I'm going to fill the form out and see what they say. It is binding for 12 months from the ruling date. I am more interested though on how much tax I will need to pay on btc withdrawals...