My father was also one extracted from Dunkirk - he said that what saved a lot of them was the soft sand caused any bombs to go down deep & just explode straight up instead of the usual horizontal blast damage. He returned to France on D Day + 1 landing with Guards Armoured Division in a REME Churchill Mk VIII AVRE.
If memory serves, one of the National Trust properties (Arlington House?) in North Devon has models of all of the Dunkirk armada.