After Tommy "borrows" his uncle's car, he reverses into a bollard so hard that it is ripped out of the ground. However in the next shot, seen from the rear, neither the bumper nor the bodywork is dented.
As tommy is dropped off by the villains, his forehead is unmarked, but as he comes into his house, he now has a cut by his left eyebrow which tuppence treats for him.
Toward the beginning of this episode, when Tommy is looking at his damaged bee hives, there is a bleeding cut next to his left eye clearly visible. Tuppence rushes out of the house to see him. When Tommy turns to face her, the cut is completely gone. When she immediately runs over and hugs him, the severe cut is back.
When the man commits suicide, he does so by allowing himself to slowly fall back off the tower. His body is then seen face down, but with his head away from he tower. If he had landed face down, his head would have been towards the tower.,
When Tommy and Tuppence are looking for a railway station, we see a steam engine and tender with British Rail emblem. The date of the story is 1952, four years after the establishment of British Railways; it wasn't renamed to British Rail until 1965.