Continuity mistake: When Steed is waiting to catch Mother's special bus. Steed has parked his car fully in the road and by a bus stop sign. As the bus arrives and parks at the kerb, Steed's car has vanished - the bus would otherwise have collided with it.
Factual error: The bad guys are supposedly auctioning off the stolen Mona Lisa. But they and their prospective buyers aren't very art savvy. The painting is more than twice the size of Da Vinci's actual masterpiece. (00:44:50)