In the final scene, Gig Young is holding Susan Oliver's hand in the close up shot when they come outside, then he releases her hand and holds both his hands in front. When the shot changes to the long, he repeats the exact same motion again.
The interiors are, presumably, shot in studio the US. But the action car sequences are some sort of 2nd unit footage shot on location in Britain. At one point the train robbers in the Bentley find the road blocked by a woman driving a Mk1 Ford Cortina. But in the close-ups (studio) she is clearly not in a Cortina. The features visible in these shots are much more consistent with the Morris Minor already being used in other close-ups.
The TV announcer says that the next program will show the finals of the "Male Alto Singing" contest at the eisteddfod. There is no such category in the Welsh National Eisteddfod.
The train engine pulling the carriages in which the robbery takes place, bears little resemblance to any engine running on British Rail during this period. I suspect that this is stock footage of an American engine.
An earlier contributor surmises that the rail scene is stock footage from the US. This is not the case. While it may be stock footage, it's shot at the Longmore Military Railway, a UK location used several times in film and TV. The loco tender even has the letters 'LMR' on it's tender. The loco is not American either. It's a British wartime austerity loco, a 2-10-0 of which there were two at the LMR in the early 1960s.