Elvis,
I am Australian with a British Passport. Visas are something I haven't had to worry about. I lived in Oz for about 35 years.
The "first" Oz ATPL cost about $50,000 but that was over many years.
The "second" JAR ATPL cost $50,000 over about 18 months.
I am now working in ops part time and about to start flying the mighty Shed for Streamline.
If you don't want to live and work in Oz I would follow CFI's advice. She's a Brit now working and living in Perth, Oz. What she doesn't know about the vaguaries of flying in Oz from the UK isn't worth knowing.
