Gene (Philip Glenister) says, "Should be doing hula-hoops", which either refers to "Hula Hoops" the UK potato snack in the shape of short hollow cylinders made by KP Crisps and first produced in 1973, or the "Hula Hoop", the plastic toy hoop that is twirled around the waist, limbs, or neck and first made by the Wham-O toy company in California in the mid-50s. In this context, it is a misquoting of the UK phrase "cock-a-hoop", meaning to be in boastful high spirits. It comes from the French phrase, "coq a huppe", meaning a cockerel (a rooster) displaying its crest (huppe).
At the end of the episode, Luigi (Joseph Long) is listening to an Italian sports commentary on a portable radio. From the dialogue, it seems this may be the FIFA World Cup final between West Germany and Italy held on 11 June 1982 at Madrid, Santiago Bemabar stadium. Italy won 3-1.
Gene (Philip Glenister) says to Alex (Keeley Hawes), "When you stop being Doris Stokes ..." Doris Stokes was the UK's best-known spiritualist and psychic medium.
Gene (Philip Glenister) says, "a theory that doesn't come from Vincent Price." Vincent Price (27 May 1911-25 October 1993) was an American actor remembered for his roles in horror films such as the Roger Corman adaptations of Edgar Allan Poe stories, as well as The Fly (1958), Return of the Fly (1959), The Tingler (1959), The Monster Club (1981), and many others.
Ray (Dean Andrews) says, "I'm like Liberace," to which Chris (Marshall Lancaster) replies, "What? A poof?" Ray comes back with, "No, I mean Valentino, I'm like Valentino." Liberace was a famous flamboyant gay American pianist and singer. Rudolph Valentino was an Italian-American actor who became a sex symbol when he appeared in silent movies in the 1920s, and was known as the Latin Lover.