After Brett is shown driving around Rome, he joins a queue of cars being stopped and checked by police. One car clearly in focus, a blue Fiat 850, has a badly made fake Italian number plate. (In some showings this shot has been cut.) Later the boys commandeer a silver-grey Peugeot with a similar fake Italian number plate. In fact it's the same number plate - ROMA 613583.
Early on there is an establishing shot of Brett driving his Aston Martin in the real Rome. After this point, however, any seemingly Italian number plates on cars are obvious fakes (made by the props department), whereas cars in the background have French number plates, revealing that the episode was mainly shot in France, not Italy.
Driving the blue van through the countryside the shots of the cab show Sidonie wearing a pink top. In the wide shots of the van's exterior she is wearing beige.
Driving along a country road shortly after fleeing Rome the dark shadow of the camera and tripod can be plainly seen against the bottom half of the vehicle.