Hi Angus,
I don't know any breeders per say, but several high quality specialist reptile store in the Melbourne area,
As you mentioned, Amazing Amazon, from what I understand, their animals come from either outside breeders, or from some of the people who work there, who are also breeders. They give some good advice, but it depends on who you talk to.
'Totally reptiles', is a really underrated place IMO, it's about 40 minutes from Amazing Amazon, so a bit of a drive. But they seriously care about their animals, and do their best to educate people. They are super honest and won't con you into buying unneeded things like some stores, they also provide ongoing advice when you need it. It's where I got my first snake and being a complete noob the owner there, gave me great advice and was willing to help. It's the kind of service you don't always get in a big store, here's their number (03) 9435 2152 They also have a facebook page. Would highly recommend checking them out, cannot think of a better place to get a first snake.
Also 'Mentone Aquarium' have quite the range of snakes, good if you're looking for something in particular, and the guy in charge of the reptile department seems nice and reasonably knowledgeable. But their stuff, especially the reptiles themselves are very pricey.
Hope this helps you out