Jonny Lee Miller appears in an early role as the 'toy boy'. He would go on to become a prolific and well known actor, starring in many theatre, film and TV productions, including playing Sherlock Holmes the US series Elementary (2012).
The uncredited actress standing to Onslow's immediate left, while they're singing "To Be a Pilgrim" in the church yard, is former opera singer Keturah Sorrell, who was then in her second career as a TV bit player.
This episode is also known as "Daisy's Toyboy".