At the start, we see the motorcycle fly into the air with various parts being flung off, including the head lamp. A few moments later, we see the bike again and the head lamp is reattached.
After the headlamp has been mysteriously re-attached to the bike upon the accident, it is still lit. Even if the engine has stopped (No sound, rear wheel is not moving; the driver wouldn't be able to downshift that fast) and the battery has been thrown away.
During the shots of the large initial cap letters being cut out for the poison pen letters, portions of lower case letters are included with the red capital letters. When the poison pen letters are shown later, there are only the red capital letters without any partial lower case.
The close up shot of the motorcycle riding is clearly green screen and the two distant shots at the end are clearly a stunt man/double.
The episode is set in 1952. Characters are seen smoking filter-tipped cigarettes from hard card cartons. Filter tips were considered a speciality item until 1954, and only became widely popular from the 1960s. The hard carton with flip top was not introduced until 1955.
Though the movie is set in the summer of 1952, one of the letters arriving to Symmington's before Mrs. Symmington's death bears a stamp with the likeness of Queen Elizabeth and a value of 1/3. The first UK stamps with her likeness were not issued until 5 December 1952 and had values of 1½p and 2½p.