Can anyone also give me an idea of teh best Mirage III kit to get for an Aussie version as well?
In 1/72nd, injected styrene, you have the new PJ Productions / High Planes cooperative effort kits. I have a boxing intended to depict a Belgian Mirage VB/BR, but a IIIO could be built as well. That's the best of the lot, though panel lines remind me of Airfix kits and I have heard some adverse opinions about the nose contour.
Other than that you have the High Planes earlier offering which are probably better in outline and have much finer panel lines but are typical "limited run" models, i.e., scary ones.
Better forget about Heller and Revell earlier offerings, though in outline they are most probably bang on.
I have never seen the earlier PJ Productions resin models, which seemed to be the same as above.
In 1/48 I am afraid that the perspectives are grim, as only the old Heller or the limited run Fonderie Miniatures can be developed into a reasonable IIIO. Modern kits (Eduard and Hobbyboss) depict the earlier IIIC model, which is quite useless without major surgery. I know of no conversion set which allows you to go from C to E-type Mirages (there is a Red Roo which could be used with a Heller IIIB, a rather strange choice)
Hope that helps,