South Gippsland.
thats not melbourne! i was going to recommend a good livestock feed place here that you can get all one desires for birdkeeping at a quarter of the price.
in any event i'm sure there are plenty of such places your way. i buy a quality finch seed mix, then mix it roughly half half with red pannicum. it seems to be every finches favorite seed.
green seed is really, really good for finches so collect as much of that as you can - some people collect it in bulk in season then freeze it.
goulds are a type of parrotfinch - which i have read are a little fonder of fruit than most. but DO feed the lebanese cucumber. the birds go crazy for it and most breeders all consider it an integral part of their standard diet these days...