In 1960, after leaving the comfort of the full-time job, Bowen and fellow advertising copywriter Jeremy Bullmore began writing together using the joint pseudonym of Justin Blake.
Their character, Garry Halliday was picked up by the BBC, who commissioned them to write a children's adventure serial for television which starred Terence Longdon in the title role.
From the early 1960s, Bowen focused on writing for television, including contributions to series such as Front Page Story (1965), The Power Game (1966) and seven episodes of the 13-part thriller The Guardians (1971).
The element of folk horror in Robin Redbreast and The Photograph was also seen in his teleplays "A Woman Sobbing" for Dead of Night (1972) and two entries in the A Ghost Story for Christmas strand; "The Treasure of Abbot Thomas" (1974) and "The Ice House" (1978).
I Love You, Mrs. Patterson (1964) concerned the romantic entanglement of a student and his teacher's wife, and Little Boxes (1968) consisted of two one-acts, the first about aging vaudevillians and the second about the attempts of a young lesbian couple to conceal their affair.
The Corsican Brothers (1970) was based on the story by Alexandre Dumas père, and the production at the Greenwich Theatre starred Bowen's partner David Cook alongside Gerald Harper.
The character of Hetty Wainthropp was loosely based on Cook's mother, Beatrice, and was portrayed by Patricia Routledge alongside Derek Benfield as her long-suffering husband Robert, and Dominic Monaghan as her sleuthing side-kick, Geoffrey.
Bowen and Cook began a romantic relationship which lasted for 52 years; the couple split their time between the flat they shared in South Kensington and their cottage in rural Warwickshire.