The brand of whisky given to Morse by Ogleby and which he proclaims "very nice" is Tamnavulin. It disappeared about 10 years after the episode was first shown but has been revived since 2016.
The man seen briefly talking to Morse's creator Colin Dexter is the scriptwriter of the episode, Julian Mitchell.
The Studio One cinema in this story is rather oddly referred to by various characters as if it were some sort of porno cinema, simply because it happens to be showing "Last Tango In Paris" - a controversial film, certainly, with sexual content that was widely deemed shocking on its initial release in 1973, but also a widely-praised one of some artistic and intellectual standing. As the film is replaced at the end of the story by a Disney animated feature, and the lobby also displays a poster for Wim Wenders's "Paris, Texas", it is clear that the Studio One is a perfectly ordinary and respectable art-house cinema specializing in revivals, of the sort Oxford was once well-known for.
Morse's home phone number is revealed to the viewer as Oxford (0865) 88318.
The patient placard on Monica Height's hospital bed identifies her doctor as "M.Reynolds". Episode crew member Mark Reynolds is listed as "dressing props" in the art department.