In early 1968, during production of the Joe90 episode The Unorthodox Shepherd, the production team took their cameras to Harefield in Buckinghamshire and shot both exterior and interior footage of the local church to double as St. David's, parish church of the Reverend Joseph Shepherd. A puppet of the villain Mason accompanied the crew to Harefield for appearances on the footpath outside the church, footage of the church graveyard established the entrance to the counterfeiters' crypt-based forgery operation and interior insert shots were filmed inside the church. After a heavy snowfall, the location crew returned to the church to shoot footage of the snowbound St. David's for the episode's closing Christmas scene.
The Unorthodox Shepherd paved the way for The Secret Service, both in its plot-line of a man of the cloth who is not all he seems to be and its use of location footage inserted into the studio-shot interior sequences. On The Secret Service, a second unit headed by director Ken Turner was responsible for finding the buildings and houses that would appear in location footage, and also the sections of country road along which the vehicles (mostly Gabriel, Father Unwin's Model T Ford) would be seen travelling. For these exteriors, the actor and entertainer Stanley Unwin was often seen doubling for the puppet Father Unwin, driving Gabriel, walking about with his suitcase, and looking out of the window of the Vicarage in the opening title sequence.
Sadly, after 13 episodes, The Secret Service was cancelled and this spelled the end for the Andersons' Supermarionation productions as they moved forward with live-action productions. The one exception with regard to locations proved to be the pilot to the ill-fated The Investigator series, which was completely shot on the island of Malta, combining puppets, flesh and blood actors and locations. Ill-fated, because the – rather mediocre – pilot program never panned out into the proposed series.