In 1911 Cawthorne's moved to 17 Rundle Street, but in 1924 those premises were demolished and an up-to-date music warehouse was built.
His father, lighthouse keeper Captain William Cook Cawthorne, arrived on 22 April 1845 aboard the Victoria, from Western Australia.
[7] He was interested in Australian Aboriginal culture and made useful observations of Kaurna language and the people's customs.
[12] He was a frequent visitor to the mission, school and camp at Piltawodli,[8] was a close friend of Kadlitpina ("Captain Jack"), loved the Kaurna Palti "corroboree" and their material culture, and was responsible for recording many names of artefacts.
[13] His Rough Notes on the Manners and Customs of the Natives, written in 1844, was published in the 1925-26 Proceedings of the Royal Geographical Society of Australasia (SA Branch).
[15] He was member of the Volunteer Military Force until 1863 when, as Captain of the West Adelaide Rifle Company, he resigned in protest at the Government's refusal to allow evening parades.
[19] He then advertised himself as a telegraphic agent, and began stocking the Illustrated Melbourne Post, later the Australian Journal and other interstate and overseas magazines at business premises in Morphett Street.
He and A. J. Chapman (of Allan's Ltd., Cawthorne's chief competitor) founded the Dame Nellie Melba Memorial Fund, and Gus served as house manager for S. Talbot Smith's Repertory Theatre.
[23] Captain William Cook Cawthorne (c.1799 – 28 September 1875) married Georgina Sarah (c.1802 – 14 June 1860).