Brendan O'Shaughnessy and Teddy Cummings reject the louvre doors, which lands Del in trouble with Denzil, who is demanding his money back.
This episode contains a rare instance of the series using video rather than film for location scenes.
This came about because the location sequences in some of the earlier episodes this series (including "Hole in One") had been filmed with Lennard Pearce prior to his death.
The BBC agreed to cover the budget shortfall, but on the condition that video be used instead of film, due to its lower cost.
The idea for the script was based on a true story of a rare butterfly that John Sullivan had read about.