Humphrey (Kris Marshall)'s napkin has a sketch of a teacup, and reads "F, G, and B of B"- Fox, Goose, and Bag of Beans.
The note in the box of college things sent by Richard's Mum had a fake address of course. However, the post code was a false Oldham OL code rather than an Oadby, Leicester one.
Although the characters were supposed to have attended university and graduated together, the ages of the actors playing them varied widely. The oldest, Sophie Thompson (Angela) was born in 1962. Tim Dutton (Roger) was born in 1964. Ben Miller (Poole) was born in 1966. The youngest, Mark Bazeley (James) and Helen Baxendale (Sasha), were both born in 1970.
The title is sometimes given as "Death of a Detective".