There is a tradition that some of Doc Martin's patients have names which are puns. In this episode the doctor called for his next patients: Scott Jegg (Scotch Egg) and Kay Cole (Cake Hole).
Marks the second time where Eileen Atkins (Ruth) doesn't appear in an episode since she joined the cast in season 5.
The joke behind PC Penhale not knowing about Stewart's past is that Stewart was in the first two seasons, when PC Mylow was the town constable.