When Cass is being released from prison, the officer who confiscates the notebooks is shown wearing sergeant's chevrons on his epaulets. There is no "sergeant" rank in the prison service. The pullover is part of a Police uniform, and they would not be involved in the running of the prison.
In the section taking part during 1983, it shows West Ham fans at Leeds & Newcastle, but the team didn't play those two clubs during that year, as both clubs where not in the old First Division at that time.
The film combines the two periods, Cass Pennant spent in prison. He was actually first entered prison in 1980 not in 1983 as shown in the film.
When the two ladies are talking outside a house with Cass in the pram, the subtitle shows 'Slade Green, London 1958'. Slade Green is now in the London Borough of Bexley, but in 1958 would have been part of Kent as the current Greater London was not formed until 1965. Also, the house types don't exist and have never existed in the Slade Green area, neither does the blue railway footbridge. Slade Green would have in 1958 consisted of a couple of farms, a railway depot, some railway worker houses and some newer council houses.
When Doll cleans Cass's wounds, a boom mic is momentarily visible above Cass's head.