Barry states that the SDP (Social Democrats) is "the party of the future". In actual fact they merged a few years later with the Liberal Party and became the Liberal Democrats. The SDP ceased to exist in 1988, a mere two years after this episode was broadcast, and seven or eight years after it was founded.
Continuing the tradition of family appearing in AFP season two, Thomas Bradford-Jones plays Henry Palmer, Sir James and Celestia's son. "That grubby little thing", as Celestia describes him, is in fact Jimmy Nail's (Oz's) son.
In joke: Mr Treadaway was named after Dick Clement's former bank manager. (He is the man in the Cross Keys who complains about his stool being taken by Barry.) Treadaway's successor at the bank was a Mr Oxlade, which is also the name of a character later on in the series (his pool is used by the lads by mistake).
as Sir James. His wife Celestia is played by Sarah Neville, who is no relation. He usually plays upper class characters. Given that Neville Hope appears in his scenes, there are perhaps three Nevilles in them.