Seems to be this film. A real oddity. The description in the second link says it all. As a bonus I never knew there was a website dedicated to buses on screen!
Although seeming rather amateur to our eyes, considering that it is a film about the travails of a previously hostile nation , it seem quite sympathetic to the British cause. And the beach scenes create a better atmosphere than the recent 'Dunkirk' I feel. I wonder if they featured the ill fated participation of the Regia Aeronautica in the latter days of the Battle?
Some of the derogatory terms for Italians used by the commentator may cause offence, but it is of it's time!