During the dancing scene at The Majestic, a bag appears over Freddie's shoulder for a brief moment and then disappears again.
The rear light on the train changes position between them jumping on the train and the train moving into the distance during the credits
When Julie asks Freddie where he'd like to travel, her globe is showing Australia then she spins it to stop on Africa. But as he chooses Cornwall, her globe is instantly showing Australia again.
During the night club scene, the song 'I believe in miracles' was sung. This was not released until 1976. In fact, some patrons dance to disco. In the summer of 1973, there was no music genre 'disco' so any such music would have fallen upon confounded ears.
The film is set in 1973, yet all of the trains seem are in liveries from the 1960's. (While it is true that the last of the crimson coaches weren't repainted until 1974, by 1973 almost all locomotives were blue and coaches blue or blue and grey.)
During the live band scene a powered speaker appears on stage
(then disappears). It's a Mackie SRM450. These weren't invented until the 1990s.