Complex sentence: At the conclusion of World War I, HMAS "Australia" sailed for Australia, departing on 24 April 1919 and arriving on 28 May, however Burnett stayed in England on an attachment to the Royal Navy with whom he served for the next seven years.
Split into simpler sentences: At the conclusion of World War I, HMAS "Australia" sailed for Australia, departing on 24 April 1919 and arriving on 28 May. Burnett left the ship before departure and remained in England on an attachment to the Royal Navy, with whom he served for the next seven years.