* Peter Yates is a movie director of films like "Krull" (1983), "The House on Carroll Street" (1988) or "An Innocent Man" (1989)
* Yolande Turner also appears in Episode #95 "A Double in Diamonds"
* Alex Scott also appears in Episodes #93 "Island of Chance", #107 "The House on Dragon's Rock", and #113/114 "Vendetta for the Saint"
* Alex Scott also appears in the first "The Persuaders" episode "Overture"
* Martin Benson also appears in Episodes #75 "The Reluctant Revolution" and #98 "The Gadic Collection"
* Robert Cawdron also appears in Episodes #4 "The Covetous Headsman", #42 "Jeaninne", #64 "The Abductors" and #90 "To Kill A Saint" (all: same role)
* Manning Wilson also appears in Episode #42 "Jeannine"
* The character of Inspector Quercy appears several times in the series although played almost every time by a different actor. It's Eugene Deckers in Episodes #4 "The Covetous Headsman", Manning Wilson in #19 "The Work of Art" and #42 "Jeannine" and John Serret in # 64 "The Abductors" and #90 "To Kill A Saint"
* Hazel Hughes also appears in Episode #35 "The High Fence"
* Neville Becker also appears in Episodes #12 "The Charitable Countess", #69 "The Saint Bids Diamonds" and #72 "The Queen's Ransom"
* Anne Sharp also appears in Episodes #7 "The Arrow of God" and #32 "The Lawless Lady"
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The same street side of the back lot was used for three different locations in this episode - the café scene at the beginning, Jean Bougrenet's flat and Mere Lafond's office.
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It's clear to see that both Roger Moore and Neville Becker are not in the later part of the fight scene (0:25). [Submitted by Wojciech Trojanowski] Notice the obvious cut from the actors to the stuntmen 
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I am pretty certain that this is still Roger Moore in disguise and not Tom Naylor (0:45).