With the exception of Digby, all the supporting cast were dropped after 1960, but two years later, Keith Watson and writer David Motton were allowed to introduce a new supporting cast, who remained with the series throughout the rest of its run.
With the exception of Digby, all the supporting cast were dropped after 1961, although Guest, O'Malley, Hogan and Sondar made occasional reappearances. In 1963, Keith Watson and writer David Motton were allowed to introduce a new supporting cast, who remained with the series throughout the rest of its run.