In the scene in the evidence room the gnomes containing cocaine can be seen in the background.
Alex (Keeley Hawes) says the names on the deciphered list are old tube station names. These are: Aldersgate, which is now the Barbican station on Aldersgate street; Chigwell Lane, which is now Debden station on Chigwell Lane; Dover street, which is now Green Park station; and, as Alex states in the episode, Gillespie Road is now Arsenal station, named after the football stadium; and Eastcheap is Monument Station, named after the monument to the Great Fire of London, known simply as the monument.
At Caroline Price (Amelia Bullmore)'s home, Alex (Keeley Hawes) picks up a purple-haired Troll doll. These were first created in 1959 by Thomas Dann, a Danish fisherman and woodcutter. The dolls have had brief periods of popularity in the UK and US in the 60s, 70s, 80s, and 90s.
Referring to photos he has obtained from the RWF women, Ray (Dean Andrews) says, "got these from one of the boilers." "Boiler" is a northern term for an unattractive woman.
Gene (Philip Glenister) says Martin Kennedy "kept a stack of Color Climax close to his left hand", referring to the hardcore porn magazines produced by the Color Climax Corporation in Denmark starting in 1969, although only watered down soft-core versions were generally available through sex shops in the UK at that time.