The phone number that Tony dials on the train is 01 811 8055, which was the phone number for Multi-Coloured Swap Shop (1976), and later Saturday SuperStore (1982), which were BBC Saturday morning TV shows from the 70s and 80s.
The musical score melody heard throughout is very similar to the main theme from Tron: Legacy (2010), which also starred Michael Sheen.
Cary Elwes is over 6 years older than Michael Sheen despite playing his younger brother in this film.
The Astoria was, in real life, owned by Barry Noble.
The film was released on 18 December 2021 in the United Kingdom via Sky Cinema and Now.