Continuity mistake: When Wallace races to get crackers, check the packet's logo. When the camera angle changes it's different. (00:08:57)
Continuity mistake: Gromit uses the handbrake to let the ship take off, but when travelling between the Earth and the Moon there is a shot of the control console and the handbrake has disappeared.
Continuity mistake: When Wallace races out to get the crackers Gromit is seen spinning in his chair, to the right of the screen is the handbrake in the down position. When the ship blasts off Gromit realises he's left it on and puts it from the up position to the down position. (00:08:30 - 00:09:20)
Revealing mistake: Near the end of the movie, when Wallace says: "hold tight lad, and think of Lancashire hotpot" one picture of a sheep on the ceiling slightly moves a few times. (00:19:57)
Chosen answer: Bognor Regis and Blackpool are seaside towns, so presumably, those are places Wallace and Gromit have been on holiday in the past. Beaconsfield is an inside joke: It's where the National Film and Television School is located and a number of scenes were filmed there.