@22K
You came to the wrong place for tax advice...., mostly because some pilots have the delusional believe that they are smarter than most people, specially people that work at a tax office...., so you get folks getting hit with close to half a million Aussie dollars bill between tax and penalties.
The funny thing is that others that see this situation, still think the tax people are stupid and what happened to the other guy will not happen to them..., because of course, I'm smarter than that other fool and some idiot working at a cubicle.
Go find one of those "work at a cubicle" types to answer your questions about taxes, as it turns out, they are actually pretty smart about that sort of thing.
Who knew?