Apparently, a number of story elements from this movie were re-worked into the Bollywood film Fanaa (2006) where an Indian woman replaces the English woman and the German spy is replaced with an Indian Army Officer who is really a Kashmiri terrorist.
When Lucy finds her dead husband in the surf, she wades into the water to get his body. A few minutes later when she's back at the farm house, she's completely dry.
The opening credits roll over scenes of British soldiers at a train station and in the background is a truck with US Army markings. After the credits, there is a title card marked "London 1940". However, the US wouldn't enter the war for another year so there shouldn't be any US military vehicles present.