Paul Eddington and Penelope Keith went on to play husband and wife in The Good Life (1975). However, the only time they appear together in this episode is during the end credits listing, as all of Keith's scenes were cut.
Steed's Bentley was damaging during filming when a generator being swung on a pulley chain clipped the bonnet.
Patric Newell, here playing Sir George Collins, would later play 'Mother' throughout the last series of "The Avengers".
The toy carousel Mrs Peel sees has knights on chargers. Appropriate, considering Mrs Peels maiden name is Knight.