Jock went to British Guiana for the first time to take charge of the family estates, arriving in 1934. The Campbells owned Las Penitence Wharf on the Demerara River, Georgetown, where they were agents for the Harrison line of shipping. They also owned Ogle Estate, up the East Coast from Demerara, and Albion, further Eastward in the Berbice district. In his first few months in the colony Jock worked at the family's wharf, assessing the claims made by merchants whose goods had been broached, broken or stolen.