When Leroy attempts to pacify a man in a cell, the man calls him an "Oreo biscuit", as in black on the outside but white inside. However, the scene takes place in the 1980's, and Oreos didn't reach the UK until 2008.
When Leroy is in the locker room, signs behind him are on A4 sheets in the Times New Roman font; this would not have been used for such everyday purposes until modern PCs and desktop printers became available in the 1990s. In the 80s such signs would have been handwritten, or perhaps printed with a different font.