A copy of the board game Scotland Yard by Ravensburger is in the stack of games inside of Billy's mother's caravan (mobile home). That game was originally produced in 1983.
Whilst the film is set in the late 1960s, early 1970s, the London underground train the Phantomlady disappears into, after Kitten ran down the escalator after her, is of the 1990s.
Although The Wombles would have been at the height of their popularity during the film's mid-70s setting, the appearances of the featured Wombles are based on the designs from their late-90s revival, in particular Wellington. Also, Alderney is shown - although included in the books, she didn't make her screen debut until the 90s series.
Patrick "Kitten" Braden: Patricia Kitten, aka Deep Throat, had penetrated the deepest recesses of the Republican sphincter... with her secret anti-terrorist spray, named after Gabrielle Coco Chanel's lucky number.