Yes, I had both of those. I was just trying to give hints without being too obvious. As soon as I had solved the anagram of 4down and the rather straightforward 9 down I knew we were in Arthurian territory which made guessing the title rather easy, which in turn led to the solution of the Playfair square and to a full grid. Just a question now of tracking the names of the 14 27s provided by the spare letters in the down clues across the grid. I've played chess since I was ten so it shouldn't be impossible.