* Jane Merrow also appears in Episode #62 "The Happy Suicide"
* Anthony Nicholls also appears in Episode #37 "The Gentle Ladies"
* Anthony Nicholls would later appear in the Roger Moore film "The Man Who Haunted Himself" (1970) [Submitted by Christopher Survela]
* Donald Pickering also appears in Episode #29 "The Noble Sportsman" (uncredited)
* Donald Pickering also appears in the episode "Someone Waiting" of The Persuaders
* T.P. McKenna also appears in Episode #101 "Legacy for the Saint"
* Terence Rigby also appears in Episode #105 "The Time to Die"
* Martin Wyldeck also appears in Episodes #29 "The Noble Sportsman", #64 "The Abductors" and #104 "The Double Take"
* Katherine Schofield also appears in Episode #88 "The Death Game"
* Fredric Abbott (misspelled here) also appears in Episodes #22 "The Rough Diamonds" (uncredited) and #99 "The Best Laid Schemes"
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Why is there always a hand in The Saint's face? Because it's not Roger Moore! (0:09)
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These scenes are supposed to be at night... but obviously they aren't (because of the sunlight)! (0:09)
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The car Templar is driving in Amsterdam is wondrously changing its colour from outside to the backlot scenes, from golden to grey. (0:14 and 0:15)
* Dutch numberplates from the sixties contain two letters and four digits.
The numberplate on the golden Chevrolet on location indeed has two letters and four digits. 
The creamy chevy in the studio has a fake numberplate. It has two digits too many! [Submitted by Matthijs Puister]
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The villains pursue Simon on location in a large blue Vauxhall with real numberplates. 
In the backlot they have changed to a smaller beige Vauxhall with fake numberplates. [Submitted by Matthijs Puister]
* All the other cars in the studio scenes (Pontiac in front of Hotel van Veeren, Beetle, police cars) also have fake numberplates. [Submitted by Matthijs Puister]
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The sign on the house of Hendrik Jonkheer says: "Hendrik Jonkheer diamantslijter". It should read: "diamantslijper". A "slijter" is a retailer of liquors. [Submitted by Matthijs Puister]
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On the door to the office of Jonkheer it says "Privaat". This word means "toilet" or "lavatory"! It should read "privé" instead. [Submitted by Matthijs Puister]
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The newspaper is fake. "Elseviers weekblad" actually exists, but it is a magazine, not a paper. [Submitted by Matthijs Puister]
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This is not a genuine advertisement. There is no brand "De Keytzer". Dutch brandy is usually referred to as "vieux". [Submitted by Matthijs Puister]
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This scene is supposed to be somewhere else in Amsterdam but it's definitely beside Jonkheer's jeweller's shop - the "H.E. Donke" sign is much too conspicuous. (0:24)
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Another
object giving away that this scene is at the same (backlot) location as Jonkheer's shop is the street sign "Weesperstraat" that is partly visible. This is where Jonkheer's shop is supposed to be located. [Submitted by Matthijs Puister]
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The green VW Beetle in Templar's back is also driving around in front of him... in the same scene! And why are the headlights of the Beetle switched on? (0:33)