Excellent find Mike, we rarely get to see WWII camo in colour. Evidently RAAF Parkes put a lot of effort into vehicle camo. The entire fleet has undergone full repaint in what appears to be a well thought out scheme. Note consistent pattern for each vehicle type, and colours well chosen to match the terrain. Like most such endeavours they've taken some licence with the colour sets approved for use in January '42. The result is a unique 4-colour scheme, which I would hazard a guess at being: Khaki Green J; Grey Green F; Dark Green M; Dark Earth T. Interestingly the Bedfords appear to display the same scheme minus Khaki Green, suggesting some experimentation / refinement. Evidently they found the official schemes unsuitable so they developed their own local scheme. Which is fair enough I reckon, given the accompanying instruction: "The colour combination selected should approximate to the colours of the country in which it is expected the vehicle will operate." On that score we can judge for ourselves in this case, thanks to colour film! I'd say they succeeded admirably, although perhaps less so on the Ford vans, which look rather pale to me.
Of particular interest are the camouflaged ambos, something extremely rarely seen, as this policy was reversed in July '42: "Vehicles carrying the “Geneva” cross will not be camouflaged." I notice even the aircraft tractor was camouflaged, despite retaining yellow for safety visibility, somewhat defeating the purpose I'd suggest! Likewise the old tanker retained some yellow patches, and what a fabulous looking vehicle it is. I reckon we should make more use of early '42 camo schemes on restos, they're an important part of Australian camo history, and what better way to make your vehicle stand out in the parade!