Peter Serafinowicz is an angry cyclist, Brian Topp is Lord Mountford, Waj is a member of an anti-terrorist squad, Blinky Ben Swain is a newsreader, Jen's hyperactive friend is the head chef at The Molecule, and Darryl the Racist is a rugby mascot. Overall, the show is the rather surreal result of a couple of American comedians being unleashed into a world populated by practically every understated background character actor to appear in a British sitcom.
Doug Whitney is played by director Spike Jonze.
The Other Marty: Dave was originally played by Russell Tovey in the pilot, but wasn't available when the series went into production. He was replaced by Blake Harrison, and all of Dave's scenes had to be reshot.