First pass and I don't think I'm going to finish this today. I have a belated party for a big birthday I achieved over Christmas and it starts early afternoon. And this is tough!
I think I met Enigmatist once in a pub in Goodge St where I used to go to do the Guardian crossword with the then manager. He saw us and introduced himself. If I remember rightly he also gave us a copy of what he considered his toughest ever puzzle.