Re #1709: I think that Scotchie was correct in #1711 when he said that it was the site of New St James church, although he was marked as wrong.
Peter was also correct in saying in #1717: "at the back of the school playing field, junction of Maison Dieu Rd and Ashen Tree Lane."
New St James was a massive church which was demolished after WW2 and the site became the school playing field. Old St James is of course the tidy ruin beside the White Horse.
Photo below from "Dover in Old Photographs" by Mark P. Smith, one of the staff at Dover Museum.