The episode is an homage to Hitchcock's Rope.
Jason Griffin (Mark Gattis) mentions wanting to be like Sherlock Holmes. Gattis would star in and co-write the BBC series Sherlock (2010).
This episode takes place in a single setting. This is an idea that Shearsmith and Pemberton would further develop into 'Inside No. 9', an anthology series where episodes all take place within an eponymous "No. 9" setting.
Unless there were "studio tricks" involved, it appears that "David and Maureen" was completed in ONE SHOT, in ONE TAKE, the perfect complement to top off this brilliant homage to Hitchcock's "Rope".