Steve,
I am unfamiliar with glass sources in Australia so I can't provide any worthwhile commentary about that. However, if you can't find any sources down under there is always Cobra Valley in the States.
I think sourcing locally (assuming availability) would be better price-wise. Ordering Stateside has shipping, duty along with whatever level of financial abuse your tax authority has determined is appropriate for a purchase like this.
Here is a link to the Cobra Valley Replacement Windscreen page, that might be helpful. Click here =>
Cobra Valley's PolyGlass Hi-Performance Optically Formed Windshields