Pigeon fancier's lung is more commonly called bird fancier's lung because the triggering species includes parrots, budgies, parakeets, turtle doves, turkeys, and chickens.
PC Penhale mentions issuing a "fixed penalty notice". These were introduced to deal with minor infractions allowing for minimal paperwork, no courtroom, and no criminal record. If the perpetrator did not accept the fixed penalty notice then courtrooms and permanent criminal records came into play.
Mommy Ellington again mentions Martin's cold and loveless childhood, saying it was just the way they did things. In the 1950s and 60s the professional medical consensus was that any show of love, affection or nurturing would ruin a child. Governmental health agencies distributed pamphlets and educational films on the horrific outcome of showing babies and children love or affection.
Rory Wilton plays Chippy Miller in this episode and a further six. He earlier played the part of Mr Hubble in episode 5.1, Preserve the Romance (2011).