With its return to St Swithin's the show changes title again: Doctor on the Go.
The writers of this episode would go on to write a series for guest star David Jason, The Top Secret Life of Edgar Briggs.
This is the second episode in a row in which Duncan gets doused by angry men in uniform.
Goof: A close-up of Waring and Stuart-Clark in the fire truck was obviously made with the truck standing still and stagehands shaking the truck. However, after Stuart-Clark has stopped the vehicle and pulled the hand brake, the truck keeps shaking.
It is revealed that St Swithin's has been in existence as a hospital for four hundred years.
Dick Stuart-Clark claims to be 31, Duncan Waring is 26. Geoffrey Davies was indeed 31 at the time of the recording, Robin Nedwell, however, was 27.
The doctors become victims of "gazumping", the practice of estate agents who go back on agreements when offered more money by another potental buyer. The word probably comes from a Yiddish term for "swindle".
William Moore (farmer Prothero) was married to Mollie Sugden, who played Duncan Waring's mother on this show.
When the boys are in the flat, Duncan is reading Doctor at Large by Richard Gordon. This is one of the books upon which the series is based.
Stripper Rita does an act as a meter maid to the song 'Lovely Rita', The Beatles' ode to traffic wardens from 'Sergeant Pepper's Lonely Hearts Club Band'.
Dick Stuart-Clark claims he's doing his first year for the fifth time. That would make him about 23 years old. Geoffrey Davies was actually 27. Barry Evans, playing an 18-year old, was 26. Robin Nedwell was the youngest at 23, though still five years too old for the part.