Cubana 400 is a regular on Saturdays routing Lands End to "SAM" towards Gatwick mid morning, in the summer I think it was Wednesdays as well.
There has been quite a few strangers over Cornwall in the last few weeks with the North Atlantic track structure obviously favouring more southerly routings.
Recent regulars have been Jet Airways A330s and B777s out of Brussels for New York, Northwest B757s from Amsterdam, Kalitta B747-200s from Brussels and an Asiana B777 eastbound from New York to Brussels.
I have only seen or heard the Emirates NY-Dubai flight once though