Well, I've bitten the bullet so to speak and had the new tyres put on the Patrol. They are the Cooper ST-MAXX all terrains in 265/75r16. I called up Bulleen Tyrepower this morning and they could do $330 per tyre and had them in stock.
Very happy with the price and they are surprisingly quiet for their aggressive tread pattern. The car drives very nicely, steers well on the highway and they feel grippy. Wont be able to test them off-road until march when I visit the Gamon ranges but should get a good idea on how they perform on rocks then.