This would be relatively easy for me to do for you. I work exclusively in aluminum, 6061 T6, for the most part.
I am curious as to the quantity of parts you need made.
Also what is your "needed" date to receive the finished materials.
Aluminum stock is reasonably priced, for the most part, and easily available, although not easily obtained in milometer thickness plates. What would be an acceptable thickness in "imperial" measurements that would suite your purpose?
Shipping from the U.S. to Australia is not cheap, but if longer shipping times are tolerable, then that higher cost too can be overcome to some extent.
You can see the kinds of stuff that I build at my web site:
All My Products
If you wish to email me directly you can at: firstname.lastname@example.org
Thanks for the opportunity to be of service,