Joy Cronk, is played by Mary Woodvine, (who is the daughter of John Woodvine, who in turn played Doc Martin's father), and last appeared in episode 2.2, Doc Martin: In Loco (2005).
Martin calls for the next patient Jermaine Mann.
Martin scolds Peter that no one uses a book to smash a ganglion cyst anymore, which is an in-joke for viewers since Martin did that in a previous episode.