Hi Hays
Abi&Dan has found the right visa - the subclass 405 Investor Retirement visa.
However, you only need $1m in total and an income of $50K pa for "regional" Australia. The higher figure of $1.5m plus $65K income is only neededfor the "non-regional" areas.
I've a feeling that NSW does not participate in this visa at all, but all the other States do.
Whereabouts would your Aunt want to move to?
By the way, of the $1m $500K has to be deposited in some sort of Goverment bond (but the yield is said to be good.) The remaining $500K can be used to buy a house, for example.
It is NOT a cheap option but the theory is that these are the sorts of levels of capital and income that one needs in order to be able to live in Oz without any sort of State help at all.
If that is not feasible for your Aunt, why doesn't she settle for some long visits to Oz instead during her retirement? She couldn't do 50/50 bwteen the UK and Oz every year, but she could still have some pretty good holidays out there once she has retired. Please see here:
Tourist Visa (Subclass 676)
Best wishes
Gill