Other mistake: After the 2 Yankees put ketchup on Lupus' head, Tanner sticks up for him. After the Yankees put Tanner in the garbage can, there's obviously more ketchup on his head from before, along with ketchup on his shirt that wasn't there before either.
Other mistake: At the end of this film, at the driving test centre, a blue Austin 1800 is parked out of the way in the background, but in the next scene it is involved in the first of the collisions.
Other mistake: After Bob crashes his car into the caravan, both Bob and Terry complain they have bumps on their heads after hitting their heads on the windscreen during the accident, but neither of their heads hit the windscreen.