Michael,

I am not the expert about materials from Kew. What I read and understand (I recieved more scans from Kew yesterday): on March 25, 1918 E.C.Miller and his divers visited a German submarine believed to be sunken on March 10, 1918. The diving position was 50.24N 5.13.10W (sorry for my first given position 0.13.10W, I had problems to read the letter from E.C.Miller with serveral typwriter letters in one space). There are some papers (letters to the admirality and vice-versa) and one pencil drawing about that submarine at Kew.

Regards
Thomas