After the rowboat is filled up with what is supposedly heavy gold bars, the rowboat should sink down considerably in the water, but it doesn't.
When Simon Templar goes to Cornwall he says he is looking to rent a cottage with a thatched roof. Buildings in Cornwall usually have slate roofs, due to the ready availability of this material there and skilled Cornish miners. Thatched roofs are more characteristic of East Anglia and other parts of England where there is a plentiful supply of willows, water reed and bulrushes.