He joined the music staff of Scottish Opera in 1989 and in 1991 was appointed Chorus Master. As well as working for Scottish Opera he was also Assistant Organist at Paisley Abbey.

In 1993 he was appointed Assistant Chorus Master at ENO and in 1994 Chorus Master, a post he held until 2004.

Stephen returned to ENO as Chorus Master at the beginning of the 2015/16 Season. From 1998 to 2002 he was also Music Director of Kentish Opera, conducting The Marriage of Figaro, The Pearl Fishers, Nabucco, Don Quixote, Die Fledermaus, Cavalleria rusticana, Pagliacci and Manon Lescaut.

He also worked as a guest chorus master for the London Symphony Chorus, Brighton Festival Chorus and Huddersfield Choral Society.

In 2006 he was appointed Chorus Master at the Nationale Reisopera in The Netherlands, a post he held until 2008. He was Chorus Master at WNO (2008–14), preparing the chorus for many operas, including Khovanshchina, Aida, Otello, Queen of Spades, Turandot, Nabucco (also Savonlinna Festival), the award-winning productions of Meistersinger and Lohengrin, Manon Lescaut and Moses und Aron (also ROH).

Notable engagements elsewhere: Opera North (repetiteur); Opera Rara (Les Martyrs, chorus master), Nederlandse Reisopera (Les pêcheurs de perles, chorus master).