The series suffered from the BBC's lack of a proper archiving policy until 1978. It was BBC policy before 1978 to wipe master tapes and reuse them for other programmes, hence saving money and storage space. 85 episodes are thought to no longer exist.
The title music, composed by Fritz Spiegl and his wife Bridget Fry, was based on "Rocking Carol", a traditional Czech carol with English words by Percy Dearmer.
Fritz Spiegl claimed to have created the theme music by turning the "Z Cars" score sheet music upside down.
Unfortunately, this show is mainly a lost television series, as only five episodes are known to exist. By contrast, nearly every episode of "Softly Softly: Task Force" (1969) has been preserved.