As Jennifer, Stefanie Powers keeps her fingernails rather short. Every time there's a close-up of Jennifer's hands, the fingernails are much longer.
In the London street scene, the London bus is displaying a French number plate 8418BX13 in addition to a British plate ODL 7. As a publicly-owned vehicle used only in London it would have no reason to have French number plates. Even if had been taken to France for any reason, the British plates together with a GB sticker would have been acceptable for temporary use on French roads.
The Albany car is displaying the registration PZ 1 on modern-style number plates, when it is unloaded at the docks in California, but both number plates are yellow with black lettering. The modern style UK front number plates are white with black lettering. Although the car was a modern replica the error in the number plates would have been noticed by the London car dealer, which believed the car to be genuine. Also classic cars tend to have white-on-black number plates.
When Mr Hart starts the old car up,to use the radio thing,there engine is taken out,and the engine makes sounds etc.
Jonathan is supposedly shopping for a car in a London classic car dealership, but if you look out the window, you can clearly see the cars on the road are all left hand drive. In England, they drive on the right side of the road.