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).
Morwenna mentions to Al about how he prefers dating the doctor's receptionists, an inside-joke for viewers since the first two very similar strong-willed and quirky receptionists were Al's love interests: first Lucy Punch (Season 1), then Katherine Parkinson (Seasons 2 to 4), and now Jessica Ransom..
While the Battle of the Chemists is going on, the numbers on the till read "80085".