I'm the one who posted about the "PoW 1943" inscription, sadly I can't be sure of the last digit.
What I do remember clearly though, is that the "W" was in the overlapping "double vee" style that the Germans used.
My mother often mentions PoWs working outside our house in Sladepool Farm Rd, they were repairing bomb damage in the road, (which was of concrete sections).
I was wondering if maybe the PoW gangs around Druids Lane/Bells Lane at that time were just doing road building and also putting in the concrete bases for the prefabs ?