It could have been used almost anywhere, friend.
There were Aussies in North Africa, Italy, England and you would find them anywhere along the CBI line: China, Burma, India.
They did a lot of ugly work up in New Guinea, which is where they taught the Japs all about jungle fighting. The Australian Jungle School at Canungra is still the best in the world. The Social Credit activist Eric Butler was one of the original Instructors when the school was set up and was a family friend. I once asked him how they chose the Instructors, what made HIM so useful, and I started asking about the weapons and so forth. He replied that, "of course" they knew all that. What the actual course was about was LIVING in the jungle, which was something that the Japanese never mastered, nor did they show a great deal of inclination to master it. The result was that the locals and the Aussies who were supplying them ran the jungles and the Japs ran the towns, but if a Japanese force wanted to come OUT of a town, they had better come in considerable force because anything smaller simply disappeared. As to his qualifications to be an Instructor, all he said was, "Well, I lived in New Guinea for three months and I was still alive, so they figured that if you could do THAT, you were Instructor material." The way Mr. Butler described the actual course, it was about 5% weaponcraft, booby-traps and demolitions, another 5% on Japanese equipment and the remaining 90% on VERY advanced fieldcraft. By the time they were finished, the Australian troops could live IN and FROM the jungle..... while the invading Japanese remained strangers to it who were fearful of the perils it held. Their standard rifle: SMLE Mark III* built at Lithgow.
You hold a powerful chunk of history, friend. Look the old girl over very carefully for FTR and other rebuild marks. Likely these rebuild dates will be on the Butt if it has not been changed-out at some time. Any markings you find, come on back here. Someone is bound to know what they are.
Hope this helps.