|13th Hussars in Mesopotamia, 1917. Source: British Empire.|
Arthur MacGregor Le Patourel was a grazier with substantial land and stock holdings when war was declared. It took nearly 12 months after that declaration to sell his land and stock so that he could enlist.
Why he chose to travel under his own steam from Australia to enlist with the 13th Hussars in the British Army remains a mystery at this stage. He had served as a private in the 3rd Victorian Bushmen Contingent during the South African War. As a man of substance and prior campaign experience, and aged 36, he would have received a commission in the AIF as readily as the British Army, though a British Army commission had more prestige. He may have responded to an invitation from a friend or relative.
After the war Arthur returned to Essendon, in time moving from Essendon to Sunbury.
UPDATE: Gunner Frederick Sydney Loch embarked on the Shropshire with the 2nd Field Artillery Battalion, serving at Gallipoli, and wrote an account of it published as Straits Impregnable by Sydney de Lough in 1917, though initially disguising it as a novel. An annotated version of Loch's book has been published by Susanna de Vries, and now called To Hell and Back. Arthur le Patourel was a friend of Sydney Loch, and drove him to the Broadmeadows camp to enlist. When Sydney returned to Australia after becoming very ill at Gallipoli, he stayed at "Peterleigh", which was Arthur's Essendon home.