When John Fitzgerald (Tom Lester) is describing to Cardew Robinson (Reggie Ramsbottom) the construction of the new Dover Port Terminal, the amount of mashed potato he uses is more than the amount originally served (notwithstanding he had already taken a portion for his own plate) and he seems to have acquired extra sausages from somewhere to represent the towers.
At the beginning of the film the sports car used by the two girls is not the same car as that used by them at the end of the film. Even though they both share the same vehicle registration number.