So, I finally got around to seeing Dunkirk (1958). It has unconvincing miniatures, stock footage of Stukas, a Bren gun, and predictable story arcs, but was enjoyable. Apparently, no one renewed the copyright, and it passed into the public domain.
https://archive.org/details/Dunkirk1958
U-S stands for serviceable, and is not a crack at the United States. They also depicted all the civilian pilots as patriotic volunteers, and never showed anyone pressed into service.