Goofs

At one point when Piella picks Gromit off the chair, just before she accuses him of biting her, you see him from the back and his tail is missing - yet later in the film it has reappeared.

When Piella leaves Wallace & Gromits Home, and cycles away. The scene pans to the hallway of their house and Piella's hat and coat are hanging up, yet she has just left.

After the opening sequence, in the Top Bun delivery van Wallace's apron appears and disappears between shots.

The bomb is knocked out of the window and gets caught in the mill sails. However, when it flies out the window, the sails have just swung past, meaning the bomb should have flown down the garden.

Near the end of the movie. Piella hits Gromit away from the bomb. When the bomb falls out of the window, Piella turns and we see an impression of Gromit on her weapon. But the impression is on the wrong side.

Grommit starts driving during the first bread delivery. Yet Wallace hands him the steering wheel. They have swapped places. Wallace is now driving. This could be regarded as an error, but there is sufficient time for them to change positions.