From the BBC's viewpoint only 16 of the 52 editions survive: their archives contain 11 on their original colour masters, and the final 5 as monochrome film prints returned from New Zealand. BetaFilm and/or ZDF in Germany hold 35mm colour telerecordings of all 39 episodes from the second season onward. They only have dubbed German soundtracks, though amongst them is one English-tracked edition not held by the BBC, A Family Affair (1971). Some prints feature alternative footage which UK viewers never saw, and vice versa. Such differences even extend to the credits, as the German copies retain the John Levene "running man" titles after it had been supplanted in the UK. A monochrome English-soundtracked 16mm copy of Murder in Munich: Part 1 (1970) was eBayed to vintage TV organisation Kaleidoscope in July 2023; in November 2024 they announced they'd married this original soundtrack to the German telerecording, effectively recreating a lost episode.
There were several differences of opinion between the BBC and the Munich-based backers. The Germans were very keen on Ros Drinkwater as Steve (the BBC were reportedly less sure of her) and wanted to toughen up the stories, increase the action sequences and make the Temples appear more affluent. This 'interference' may have led to the show's demise.
Francis Matthews was Durbridge's first choice for the lead rôle, having worked together previously on The World of Tim Frazer (1960).
The first series the BBC made as an international co-production. UK prints credit Taurus Films as co-producers, whilst the German versions refer to ZDF (Zweites Deutsches Fernsehen). This was due to creator Francis Durbridge's popularity in Germany - the author himself didn't write for the show, although his 1970 books "The Harkdale Robbery" and "The Kelby Affair" were seemingly devised for it - and allowed the series to venture overseas and widen its casting base. The videotape masters were copied onto colour film to air in Germany.