I remember reading somewhere that the (unwritten) story of Rolls-Royce armoured car patrols in the Anglo-Egytian Sudan is quite special.Good photo and a good find. I've been chasing a photo of a Peugeot ambulance donated by a Toorak matron in 1914 but without success. The AWM doesn't have a specialist curator for early machinery. There are lots of military history and military vehicle enthusiast people about online. The AWM has a large amount of material available online for the WW1 period. Combine with the now rare and expensive battalion histories and Bean's multi volume history and you can turn up quite a lot. I turned up twenty pages on a request from an old lady for more information on her uncle who died at Pozieres. Sad thing was I realised I knew more about his fate than the army ever told his parents.
Unlikely that vehicle in that form ever saw service. By 1915 people were building serious armoured cars but they were of no use on the Western Front. The British used some in the desert, don't know about Australia. Peugeot built a series of useful looking armoured cars they sold to Poland at wars end.
From a historical point of view - what was the vehicle purchase policy of the Army? Was the vehicle a donation?