Richard Johnson reprises his role as Brigadier General Faulkes. He first appeared as this character in Season 1 "No Need To Know" (1981).
Father Paddy McGuinness is the second of Higgins' brothers to appear in the series. The first is Elmo Ziller, who appeared in The Elmo Ziller Story (1982).
Incidentally, Donald P. Bellisario, creator of the series, and writer of this episode, doing the cameo as the desk clerk perusing a Playpen centerfold, some years later became the father of Troian Bellisario, who starred, as main cast character Spencer Hastings, in Pretty Little Liars (2010).