Factual error: During the opening credits, the show's copyright date is shown in Roman numerals as MCLXIV. In Arabic numbers, that's 1164 - it should have been MCMLXIV for 1964.
Continuity mistake: The father tears the children's advert for a nanny up into 8 pieces, but when it comes out of the chimney it's in far more bits.
Continuity mistake: When Daffy is clawed by the bear, he loses his hat in the process. But when we Daffy running in the next shot, the hat is back on his head again.
Continuity mistake: When the gang make a second visit to the waste ground to test the go kart's new engine, Patchy is wearing a light coloured skirt, a button through front jumper and shoes. She is also carrying a small bag. In the next shot she is wearing a different skirt with pockets on the front, a different jumper with no buttons on and boots, and the bag she was carrying has also gone. In the last shot of this scene she is back to the clothes she was wearing at the start. (00:19:35 - 00:21:40)