Referring to Rosebury-Sykes, Gene (Philip Glenister) says he's "a member of the funny hand-shake brigade", meaning that he is a Freemason.
Alex (Keeley Hawes) mentions a "cognitive interview procedure." Cognitive Police Interviewing was developed in 1984 by Geislmein and Fisher and their colleagues in response to ineffective police interviewing techniques.
At three points in this episode when handling the gnomes-by Ray (Dean Andrews) at the scene, Chris (Marshall Lancaster) back at the station, and Alex (Keeley Hawes) when she picks one off her desk and drops it in the bin-gnome-like laughter can be heard. This is a subtle reference to the David Bowie single, 'The Laughing Gnome'. First released in 1967, it was a flop, but was a chart hit when re-released in 1973, and flopped once more when re-released in 1981.
Alex (Keeley Hawes) asks, "Where's the rape suite?" It was Charles Stewart, a BAFTA award winning director and cameraman, and Roger Graef's controversial TV documentary A Complaint of Rape (1982), filmed as they followed the Thames Valley police, that led to a major change in the way sexual assault victims in the UK are interrogated. Victims had previously been questioned at the police station by male police officers who acted on the crude theory that if the victims couldn't stand up to their interrogation then they would be unable to survive the court cross-examination process. In the case covered by the documentary, because of the lack of forensic evidence, virtually the entire case rested on a brutally raped 14-year-old girl's ability to withstand what many felt was a merciless cross-examination in court. Rape suites are now set up in private houses where the victim can tell their story to a specially trained female officer, out of uniform and without fear of intimidation.
Gene (Philip Glenister) says, "more beaks than Daffy Duck at a family knees-up", referencing the famous Warner Brothers cartoon character created in 1937. "Beak" is a UK colloquilism for a judge or magistrate, and a "knees-up" is a party.