I think it is called "Slapton Sands". It's very well documented, but only in recent years. Because so many toops were killed there when German E-boats got in among the landing craft during an exercise the US goverment covered it up and made it an official secret for many decades. Appeals like your don't usually work because there are so few WWII soldiers left. In the case of Slapton Sands chances would be even slimmer. The death toll there was enormous. Thousands drowned because they were weighted down with invasion equipment. Then the survivors were sent to France where they faced death again. Your best chance is to see if there is/was an association of survivors.