Ive been to an aluminum specialist, security doors, or even plumbing supplies. All these places will have the mesh with a larger spacing than the common ally mesh from supercheap and autobarn.
The mesh mitsubishi used isn't the usual 'expanded' crap, it's actually made from separate wires rather than a flat sheet. It's still available from Mitsi (I guess an aussie dealer would be able to get it for you if you gave them the part numbers?) but it's bloody expensive!
It looks a zillion times better than the expanded mesh crap though...
Yeah, the genuine mesh is ridiculously expensive. I got it new about 4 years ago, and to be honest you'd want to be sitting down when you hear the price.
Like about $850 all up last (and final) time I inquired. The back of my head's still aching from when I fell over backwards. I'm a bit of a whore really so ended up using plastic gutter guard from Bunnings. The mesh is a fraction smaller than original. However it looks the same and comes in black and lighter B)