Some of the cast were unknown, though Melvyn Hayes was an established adult actor, Gillian Bailey was fairly experienced for a child actor and both Brinsley Forde and Michael Audreson had appeared in "The Magnificent Six and a Half", a series of Children's Film Foundation films on which the Double Deckers were based. Hayes also wrote the episode "Man's Best Friend", co-wrote the episode "Get a Movie On!", co-wrote the series' theme song, and acted as a dialogue coach for the series. Bailey is now head of the drama department at Royal Holloway, University of London. Peter Firth has gone on to a prominent acting career, appearing in "Equus", "The Hunt for Red October", "Tess", "Pearl Harbor" and "Spooks" (known in some territories as "MI-5"). Co-star Brinsley Forde later became the lead singer in Aswad.