He joined Decca in 1957 as a member of the A&R department; the first recording he produced for the company was Joan Sutherland's first Decca release. Minshull also produced Antšl Dorati's cycle of the complete Haydn symphonies and Charles Mackerras's Gramophone Award-winning cycle of Janšcek operas.

He signed Charles Dutoit and the Montreal Symphony Orchestra to the label, as well as Radu Lupu, Pascal Rog_, Andršs Schiff, Jean-Yves Thibaudet, Riccardo Chailly and Cecilia Bartoli.

Minshull was appointed executive vice president in 1981, a position he held until his retirement from the company in March 1994.