Bring them to where? Australia and New Zealand had already formed military units to oppose the Germans. For Australia, these first units departed for the Middle East to under go training and refitting in early 1940 with the intention that these units then move to Europe to face the German forces there as had been the plan during the First World War. Also like the First World War, these plans went awry. Just as the entry into the war by the Ottoman Empire derailed the plans for the Australian units in the Middle East, so to did the Fall of France in 1940. The Fall of France meant that the Allies no longer had a continental front that allowed them to face the German army head on. While this was true in Europe, it was a different story in North Africa where Germany's ally Italy had colonial possessions that could pose potential threats to British holdings and shipping routes in the Mediterranean and the Middle East. This led to the launching of Operation Compass which saw a British force of about 30,000 - 36,000 men crush the Italian 10th Army, numbering around 150,000, in Western Egypt and Libya. This campaign, known now as the Western Desert Campaign, lasted from 1940 to 1943. This meant that the operational timeline for the Western Desert Campaign encompassed the period when Britain was at most risk of invasion by German forces meaning that Australian Army units would have been unable to be moved to Britain due to their existing deployment to North Africa and the Mediterranean. That said, quite a large number of Commonwealth pilots served as part of the RAF during the Battle of Britain.

Source: Desert Boys by Peter Rees