Revealing mistake: In almost every episode where Michelle is a toddler, you can always see her look to the right or left to most likely a person telling her what to do.
Cycle Crazy - S3-E13
Revealing mistake: In "Cycle Crazy, Series 3, Paul rides through the tunnel on his bike only to ride out again when a big truck comes the same way. It is obvious that the shot of Paul and the lorry are two separate shots, because after Paul comes back out, the trees don't follow the same pattern as the previous shot. This also happens between the shots where Paul rides into the tunnel.
Revealing mistake: The "hostage" episode reuses footage from the "Dinosaur" episode, which doesn't totally fit. When the giant crabs attack and destroy the group of houses on the island, the longshot of the damage is recycled from the earthquake episode - including an earth fissure, something the giant crabs wouldn't and probably couldn't have done.