Let us not forget the problem encountered with the reverse flow Proteous turbo-props which also did their part to delaying Britannia success, even after service entry.
That couldn’t of helped US sales when they knew that their own turbo-jet airliners would be well up and running in the time frame.

Britannias were used by Aeronavas de Mexicana, Cubana, Canadian Pacific, and Transcontinetal SA of Argentina, so did see some continental action.