Hi Peter
I enquired about anodizing at my local aluminium supplier, he told me that it would be $100 for anodizing whether I wanted one piece done or a pack.
I would ring Goodalls in Bendigo ask for Andrew, 54436910 and ask him of a place in Melbourne he did give me a name and number but its long gone now. I remember he said that it was the only place they knew of.
Regards