The prize I got this week wa for Mephisto 2573 (not the prize yet, just a card to say I was one of the winners). No, I didn't win the Araucaria Christmas one - I haven't seen the list of winners. I did complete it and enter, but without paying any attention to the numbers and letters. I have seen an explanation for these in these columns, but I've forgotten what it was. I think it was to do with the century in which the subject lived. If I can find out more from the Guardian Xword page I'll let you know.