Just after the policeman delivers the secret letter to Clive Sutton, he calls his secretary and starts to read off the names of the people he wants to see in his office. The piece of paper in the close-ups is different from the one we see in the long shot.
When the air-raid siren sounds, we see an elderly woman in a red coat and black hat running toward a department store door. Seconds later, after we see the police car and other people running, the camera goes back to an overhead view of the square. The same woman is now standing in the middle of the square, well away from the doors.
When the Kemp's next door neighbours are stopped in their car by police on there way to Lincolnshire, the father rolls up the window at the end of the shot but the camera and camera man are clearly visible in the reflection of the rolled up window.
Despite having been born and grown up in the primitive post-war "society", Ruth's daughter Jane has a tooth filling. She also has pierced ears (the piercings have been filled with wax but are still obvious).