The shots of Smith's flight to Brazil are of three different aircraft: both the first two are de Havilland Comets - a Comet 4 at take-off and a Comet 1 in the air (this version was not capable of transatlantic flight) - but the plane seen landing in Brazil is quite different - possibly a Douglas DC3.
When Smith enters the office of the coffee importers in Rome there's a company sign on the railings by the door. When he got out of his car in the preceding shot there was no notice.
In one of the scenes that purports to be in Brazil the vehicles are driving on the left side of the road instead of the right.
Smith is driven to the police offices in Rome in a right-hand drive car - not what they use in Italy.
The two hoods following Smith pull up in their car when he enters Scotland Yard and later when he goes to his home. The same shot is used both times.
In the initial raid, when the car drives off, the film crew is reflected in the car's window.
When the Interpol boss tells Smith he's going to Brazil, he says the flight leaves at 12.50. Yet the whole of the intercom conversation in which he arranged this has been audible and no mention of time was made.