He began work at the company in 1954, and as managing director from 1974 to 1984 oversaw its transition from a farmers' cooperative to a publicly listed industrial conglomerate.
[2] After the war's end, Bennison and his new wife initially settled in Armidale, New South Wales, where he studied agriculture at the New England University College.
Keith Edwards, the assistant general manager of Wesfarmers, saw his notice, and after a brief interview offered him a job as a "one-man budgetary control department".
It had highly diversified interests, but had weak cash flows and lacked the capital reserves needed for growth.
He met strong opposition from the board of directors, but eventually had his way, and an initial public offering was made in November 1984.
Bennison retired five months earlier, in June 1984, and was replaced by Trevor Eastwood, whom he had hired as a cadet engineer in 1963.
[5] Bennison was created an Officer of the Order of the British Empire (OBE) in 1981, for "service to primary industry", and was made a Member of the Order of Australia (AM) in 2008, for "service to business, particularly in the primary industry sector through the promotion and development of commercial opportunities for farmers, and to the arts".