Continuity mistake: When Jack goes to the surgery to take his pleasure with the nurse, he chalks on the blackboard on the door that the nurse will be unavailable for 30 minutes. When Blakey arrives, the 30 minutes note has gone from the blackboard. But when Blakey opens the door with his passkey, the 30 minutes note has re-appeared on the door.
Revealing mistake: At the beginning of the film, Stan reverses the bus into the manager's car. While the manager is under the bonnet looking at the engine, causing it to fall on him, you can see a rod with padding on it to stop the bonnet from hitting the manager. It is gone in the next scene.