All four batteries had originally gone out to Egypt with the 2nd Mounted Division in April 1915, but did not proceed to Gallipoli when the division was dismounted for service there. Instead, they variously served on the Suez Canal Defences, as part of the Western Frontier Force in the Senussi Campaign, or in Aden where B Battery, HAC and Berkshire, RHA fought a sharp action at Sheikh Othman that removed the Turkish threat to Aden for the rest of the war. They rejoined 2nd Mounted Division on its return from Gallipoli in December 1915, however, the dismemberment of the division began almost immediately as units were posted to the Western Frontier Force, Suez Canal Defences or to various other commands.