Continuity mistake: When Arthur first goes into his room with the new Brian Slade record, you see him lodge the top of his chair under the knob of his door, but after he starts the music, they show him laying down on the carpet, and you can clearly see the top of the chair facing away from the wall.
Continuity mistake: One of the newspaper headlines is "Singer Brian Slade charged with cocaine possession" but the article which it headlines is about something else entirely. It starts off: "Hotels were given a roasting yesterday over the decline of the Great British breakfast"