I can only proffer the folk etymology. Melbourne University is The Shop because it's close to the downtown area of the city, i.e. the main shopping precinct. Monash University was built much later on land that, at that time, was right among city-fringe market gardens in the suburb of Clayton, hence The Farm.
“It was the New York Times that broke his heart,�? said Nancy Packer, a retired professor of English at Stanford, who knew Stegner well in the time he nurtured writers from Ken Kesey to Larry McMurtry here on the Farm, as the university is known.