The Robinson-LaMotta title fight (2-14-51) was 60 days before Truman relieved MacArthur of his command - -both reported in the same news bulletin on the shortwave radio. That was followed by "Wheel of Fortune" by Kay Starr, which was not released until a year later (February '52).
In the closing aerial shot, zooming down to ground level just after Bentley has been executed, in the next street above the Bentley home there are visible several modern saloon cars from the 1980s, although this is 35 years after the events depicted
In the scene with Craig and Bentley by the railway line, the approaching train is pulled by engine 76079. This is a former British Railways 'Class 4MT' locomotive which wasn't introduced into service until 1953 - after Derek Bentley's death.
When Bentley, Craig & the other lads look at Stella when she's passing the cafe they're in while a passenger in the Cadillac, an Austin Allegro is clearly seen. The film is set in the early 1950s but Allegros were not launched until 1973.
William Bentley tells his son that no-one had been hanged in the 20th century where the jury recommended mercy and the Judge agreed. He may have been trying to comfort his son, but the Royal Commission on Capital Punishment (1953) Cmd 8932, note 5 on page 11, states that there had been six such cases in England and one in Scotland between 1900 and 1949 when this had happened.
At about twenty minutes to nine on the final day depicted in the film, the three adult members of the family each look at the clock in turn. The third time the clock is shown, it is one or two minutes earlier than the first two shots.
In the scene where Derek goes to Chris's house and Chris comes to the window, when Chris tells Derek to leave he draws the curtains and turns the light off. In the next shot in his room the light is on.
In the courtroom scenes where it shows Bentley and Craig sitting, it shows Craig's right arm in a sling. But when they come back into the courtroom after the jury deliberation, his left arm is in a sling.
Prior to his execution, Bentley is wearing a tie, which hangman Pierrepoint removes. British protocol was that the condemned would be given their own clothes to wear on the morning of execution, but NOT a collar (they were detachable back then) and definitely NOT a tie.
The day before Derek's execution on 27 January 1953, William Bentley says to his wife, "I'm writing to the Queen...there's nothing more we can do." Elizabeth was not crowned Queen until 2 June 1953, just over 4 months later. George VI was still King.
When Bentley and Craig climb over the gate, just before their ill-fated shootout, it appears that the stuntman for Craig is much bigger than he and it is possible that this stunt man is the same one used for Bentley's character as well.