Early in the show, when talking with the Mexican border guard, there are three people in Evan's car (him as the driver, his wife next to him, and the wife's aunt in the back seat). But, in the very next clip, as the car is slowing to park alongside a curb, only Evan the driver, is in the car. And, after the car has stopped, all three people are now magically back in the car.
American actress Mary Scott's British character loses her English accent halfway or so through the story.
Mrs Tait (Janet Wallace's aunt) tells Evan Wallace that Westminster Abbey was consecrated in 1050 and is over 900 years old. In fact, it was actually consecrated in December 1065, making it 892 years old at the time of the story in 1957.
When Evan is finishing up his examination of the car at 13:30, the boom is reflected in the windshield.