 Crombie was born in Brisbane , Queensland , on 16 March 1914 to David William Alexander Crombie , a grazing farmer , and his Indian @-@ born British wife Phoebe Janet ( née Arbuthnot ) , the daughter of Lieutenant General Sir Charles Arbuthnot . During his youth , Crombie was educated at the Sydney Church of England Grammar School in North Sydney . Completing his schooling , he was employed as a jackeroo on his family 's property near Warwick , Queensland . In 1934 , Crombie enlisted in the Citizens Military Force and was allotted to the 11th Light Horse Regiment . His service with the unit was to last until 1938 , by which time he had obtained the rank of sergeant . 
