My brother and his family invariably go out for Xmas lunch, and curry is frequently on the menu. I would not have any worries if I were you as to the willingness of restarauteurs in general to open on Xmas day, but make sure you BOOK FIRST! We're off to Italy again this year 'cos our friends are getting married on 22 Dec and no point doing Bxl-Trn-Man in the space of three days. A sad one this year as my Gran-in-law (if such be possible) snuffed it earlier this year so the famous Xmas agnolotti will be less tasty than memory makes them.
Great steaming lumps - Christmas talk already? I'm surprised at you all. Still, it's better than Big Brother. To engender conversation: "How is everyone?"