Just before the closing credits role, the 5-bar tone from Close Encounters of the Third Kind (1977) can be heard in the background.
Glynis Barber (Cheryl Brooker) and Michael Brandon (Colonel Charles Norton) are married in real life.
Mark Williams, Mark Rice-Oxley, Glynis Barber, and Michael Landes all played in different episodes of Marple (2004).