I'm pretty sure abranet is abranet, but I buy mine in boxes of 50 in sheet form rather than disk form. I get mine from a local tool company in Inverness, which is the best value I've found, but you can also get it from Turner's Retreat and a few other places - not much help to you in Australia I know. Ebay is generally the most expensive way possible to buy it, because all they do is buy a box of 50 then split it up and sell it in small quantities for more than they paid for it, so it's worth doing a bit of research and shopping around.
On the face of it, it does seem very pricey stuff, but it lasts much longer than any paper or fabric backed abrasives I've ever come across. Having said that, you don't have to use abranet - that's just my personal choice of abrasive. If it does a good job, whatever you use now will be just as good.