The first time we saw Barnaby (and Jones) wear scrubs in the mortuary.
Normally, British TV series use the prefix 01632 for their telephone numbers but at 28 minutes and 47 seconds, Jones offers his card which insinuates that Causton police station is in the 01508 STD area (full number 01508 312244) which, in reality, is the STD code for the Brooke area of Norfolk. It is also the number Troy showed in his final appearance as Barnaby's sidekick, The Green Man (s7e1).
The house being sold by Will has an estate agent sign for Beauvoisin estate agents. This company has appeared in several episodes. Olive Beauvoisin is an estate agent appearing in several episodes of the ITV crime drama Midsomer Murders.
The first outing for Tom's new car, a Volvo S80 (AA08JOJ) replacing the Jaguar cars he drove in the previous 3 series.
"If you are caught in a storm and are afraid of lightning hold up a 1 iron. Even God can't hit a 1 iron." Quoted By George Bullard is credited to the golf pro Leo Trevino in 1975 after he was struck by lightening whilst playing in the western open.