If your pulleys are 3/8" wide rather than 1/2" wide, you need a different type of belt. The A through E section belts are industrial types for high power use on fairly large diameter pulleys. For tighter radius pulleys you use an automotive type of belt, only 3/8" wide. This is usually called a 3L belt section. You can find them here:
http://seekbelts.com/beltsizes/3lfractionalwedgewrappedvbelts.htmlI don't think you'll find 3L section belts hard to get:
http://www.vbeltsupply.com/ecommerce/kevlar-corded/3lkThis seller has 3L belts in 33, 34 or 35 inch lengths, with Kevlar ropes, for US$4. I don't know what the availability is in Australia, but it doesn't seem like they are a scarce item internationally.