Based on the book "London rules" by Mick Herron.
In the end credits, the episode is dedicated to John Usher who was the a costumer on the show as well as many other film and television productions such as Allied, Jane Eyre, Paddington, Mission Impossible Rogue Nation, Wonder Woman, Paddington 2, and The Old Guard. The cause of death has not been publicly disclosed.
The contact name Lamb has in his phone for Catherine is "Old Soak", which is a informal and humorous term for an individual who is often intoxicated. Catherine is a recovering alcoholic.
The episode title "Bad Dates" may refer to a line in Raiders of the Lost Ark uttered by Sallah after he saves Indy from an attempt on his life by snatching a poisoned date out of the air that Indy had tossed to catch in his mouth.