Lynne Frederick's southern accent tends to wander between southern England and southern US.
Until now the Beer Garden has always seemed to be the Liberal Club. In this episode it suddenly seems to be overrun with Conservatives. The fact that Dolly Longstaffe and the stuffed bear that holds hats and canes are there mean that it is the same club that we have seen throughout.
The play that Lizzie and Mrs Carbuncle attend is called "The Noble Jilt".
The first time that Penelope's Keith's character's name is mentioned by Lady Fawn she calls her Flora, but from then on she is called Clara.
Sergeant Bunfit Bunfit gets his pronouns mixed up. After describing how the maid will have assisted a professional thief he says: "But no doubt he let her in, showed her where to go, and told her what he might expect to find."
The Pallisers' London home is at 25, Park Lane.
The end credits omit the hyphen from John Glyn-Jones's name.
Plantagenet is obsessed with a decimal currency system. The UK would not adopt this system until 15 February 1971, just three years before this series was made.