Thanks to everyone who suggested ideas via Facebook or Twitter, especially but certainly not limited to Anna, Beatrice, Brenda, Carol, Jan, Kiran, Mel, Niall, Nick, Owen, Rach and Sarah.
Thanks even to those who suggested steak and kidney pie (ah, no), cheese (ahem) and the Linda McCartney Celebration Roast (not to diss Linda, but this wasn't quite what I had in mind).
What we're seriously considering
Souffle (if we can find a dish in the next few days)
Things I like the sound of and might cook over the break anyway
Filing away for future reference
Parsnip pudding (sounds curious!)
Goats Cheese And Spinach Pie
Cheese And Leek Pie
Choux Pastry Ring
Puy Lentil And Vintage Cheddar Loaf (or, on a similar note, Lentil And Cider Loaf)
Vegetarian haggis with roast vegetables
Minimalist Baker (not sure how Christmassy it is, but I love this site so thanks to Mel for suggesting it anyway!)
Oh... and here's a rather nice recipe for German Christmas Biscuits (Lebkuchen) I put into practice this Christmas.