Two of the girls on the Pepsi Max roller coaster are briefly replaced by adults.
The ring in the model pig's nose changes from horizontal to vertical before and after the pig is cut in half. The blade would otherwise have had to cut through the ring, which is intact throughout.
A car disappears from behind Simon as he rings George's doorbell.
The canal water is calm after Simon falls into it.
Simon Garden's correct job title would be "probation officer" in England. "Parole officer" is an Americanism, and is probably used for the international market. However, while "parole" is used in the title of the film, "probation" is used throughout the film script.
CMT buses operate in Liverpool, not Manchester.
When Kirsty breaks them out of jail with the stolen van, the fake wall is visible.
During the roof scenes crossing over to the bank, the ventilation tower of the Mersey Tunnel is clearly visible. It is a Liverpool landmark.
During some of the scenes outside the bank, the sea can be seen down the street, e.g. when Simon meets Emma, dressed as a prostitute. Manchester is inland, whereas Liverpool (where the scenes were filmed) is beside the Mersey Estuary.
It is never explained how the conspirators have such detailed knowledge about the lay out of the bank.
George mentions that 1962 was the year that the American pop band The Beach Boys formed. While their first album "Surfin' Safari" did come out in 1962, the band formed and released their first single in 1961.