Throughout the film in particularly the street scenes there are countless buildings with plastic windows and in some cases plastic doors that were not available until at least 1980.
At around 55 minutes Reg is with a policeman at a fishing pond. The pegs (fishing positions for anglers) are made from modern scaffold pole and wooden board construction. In the late 1950s angling waters would have only had bare,natural sloping banks to fish from.
When Ronnie is in the police station waving a cigarette lighter in the face of the police officer it is obviously a narrow, stable gas powered flame. Cigarette lighters at that time all contained a wad soaked in petrol with a wick, the flame was often wide and smoky.
When the Krays are celebrating their success with Champagne they are drinking from flute shape glasses. These were not in general use until at least 20 years later.
Champagne was drunk from wide top shallow glasses.
The style of glasses Ronnie is depicted wearing wouldn't become broadly commercially available until several years after the events of the film. Ironically, the real Ronnie Kray wore a style of frames called browlines, which were popular in England at the time of the film's production and would've been readily available to wardrobe.
The portrayal of Jack Spot (real name Jack Comer) is incorrect-the real Jack Spot was a portly balding man of Jewish extraction-the characters appearance would been better suited to Billy Hill another major London underworld boss of the time.