591 Corporal John Siddle enlisted with the 3rd (Bushmen's) Contingent on 10 February 1900. He embarked for South Africa from Melbourne on board the Euryalus on 10 March 1900, arriving in South Africa on 3 April. Siddle was separated from his unit at Eland's River on 2 September 1900, rejoining a hort while later on 11 October 1900. He was wounded at Wolvers Kuil on the 14 February 1901. After spending over a year in South Africa, the 3rd (Bushmen's) Contingent embarked for Melbourne on 9 May 1901.

Siddle later returned to South Africa and enlisted for service with Steinaeker's Horse in February 1902 at Maritzburg, Natal. He was discharged in August 1902 and returned to Australia in 1903.