The composition Dudley is working on at the beginning of the episode is called "Samson and Delilah," a biblical story involving someone's hair being cut off. This foreshadows the mystery Jonathan and Carla are called in to solve.
The house used for "The Firs" is the same one used for the David Suchet Poirot episode "The Double Clue".
The musical of Samson and Delilah which is being written by Jack Dee's character, also happens to be the subject of Camille Saint-Saëns most famous opera, Samson et Dalila. Saint-Saëns being the composer of Danse Macabre, the theme tune of the show.
A partial list of the tracks contained on the fictional album "Hoes in da Hood" by Booty Posse- "Hoes in da Hood", "Easy Does It", "Doggystyle", "Gangsta Rap", "Customer".
The envelope that contained the hair and the video had Dudley Houseman's address in Berkshire with the postcode GU17 3UP.
GU17 is a Guildford post code that covers the village of Blackwater in North East Hampshire. Its not real as only 9 and 0 are used.