Ben-
There is a company out of Chicago called Sanchem that makes two products that are conversion coatings much the same as Alodine. The products are much more environmentally friendly than Alodine, in that, they are chromate free and for that reason you may be able to obtain them in Australia.
Sanchem makes a product line called SafeGard. The SafeGard conversion coating products each have quite different application methods ... the products most suited for our application are Sanchem CC-6100 and Sanchem CC-3400. I used the CC-6100 on my project.
Below is a link to the Sanchem web site with the SafeGard product line shown.
https://www.sanchem.com/aluminum-pretreatment-conversion-coatings.html
Happy building,