Hi Hugh,
I have spoken to my friend and he does not know the name of the German, however, he has reason to believe that he may be buried or at least the plaque or whatever mentioning this guy is in the St Barrwg Church in Bedwas. Which I believe is near Caerphilly and Trethomas. He has also found out that he has relatives buried at the same church, name Carter.
The name of his ancestor who came from Caerphilly is Rachael Lewis, ( not sure if her first name is spelt right ) and she married a gent by the name of Percy Carter, ne came from devon.
It was Rachaels mother who was conected with the German soldier. It is not known why the German Officer was in the area pre WW1, maybe there was a training area they used or something like that.
Many thanks
Tony