There are many Avian specialists in Australia and New Zealand, and we have more than a few members here that are from all over Australia that may be able to help you find the closest and most reputable one to you. Have you done a search online for one? I've not ever heard of anyone in Australia having a problem finding a Avian Vet, a Reptile Vet, etc.
Also, if you can't afford to feed your birds pellets as their main-staple, and you have to feed them a seed-mix as their regular, daily, staple diet, please, please make sure that it is a seed-mix that contains NO SUNFLOWER SEEDS! If they eat sunflower seeds on a daily basis they will without a doubt end-up with Fatty Liver Disease, which is the main reason that most captive parrots die long before they should. Also, try to find a seed-mix that is fortified, and that is also "varied", meaning it's not just seeds, but also contains different grains, legumes, and veggies, and little to no nuts, due to the fat that they contain. And definitely no peanuts, as they can carry mold and different fungi.
And they also should not be eating fresh fruit every day, in fact they should only be getting fruit 3-4 times a week at most, and in very small quantities. This is because all fruit is loaded with natural sugar, which simply ends-up being stored as fat in their liver, just like the fat from the sunflower seeds and the nuts become. So lots and lots and lots of fresh veggies every day, that's a great replacement for the pellets if you have to do it that way (never onions or avocados, they are toxic), lots of different veggies and dark, leafy greens (no iceburg or other watery lettuces, they are worthless and contain no nutrition at all)...Dark, leafy greens such as Mustard, Turnip, Dandelion, Collards, Bok Choy and Pak Choy, Spinach, Romaine, Chards, and other dark green, leafy lettuces, and then pretty much any and all fresh veggies except onions. Bell Peppers, all different types of squashes, broccoli, cauliflower, green beans, peas and pea pods (my guys love pea pods), carrots, okra, sweet potatoes, and eggplant are all great choices for them, and you can make different "Chop" recipes where they get a little bit of everything at once....But again, limit all of the fruit to only a few days of the week, and in very small quantities...and no seed-mixes that contain any sunflower seeds at all, or nuts, especially peanuts.
It's okay that you can't feed them pellets for one reason or another, but you then really must make sure that what you are replacing the pellet-staple with is extremely healthy and not loaded with fat, sugars, oils, etc.
