I take DD into the office with me (I have to go in for a half day - but it's full of DCs all over and very relaxed). DH used to go for coffee on the main shopping street nearby and meet us once we'd left the office, but he now has to also work (all day). DD and I would wander past the "Live Crib" on our way to meet DH (sometimes there are choirs there singing as well, as it's on the doorstep of the Lord Mayor's House).
We go into M&S, to get DD's birthday cake (26th Dec) and any other last bits we want or see that are handy. We might want a couple of other bits and pieces of shopping, but very little.
We go for lunch - sandwich and coffee type meal - somewhere that isn't utterly heaving (there's 1 café that we have tended to get lucky in for quite a few years, just off the main thoroughfare).
Head home where we work on the prep - cleaning and chopping veg, DH making the stuffing (including the traditional phonecall asking his DM how to cook the sausage meat, and she traditionally tells him that she doesn't know, she just does, and then he boils it with onion until it looks done-ish). DD makes the cookies for Santa (depending on time available, we make them from scratch or take out a half a log from the freezer that I always stash earlier in December and she just slices and bakes). Christmas music or a movie are going while we do this.
Dinner is a buffet/platter style meal - cooked and cured meats, cheese, olives, cherry tomtatoes, hummus, breadsticks, carrot and pepper sticks, prawns.....just yummy picky things (generally all cold).
Then we go in and DD lights the Christmas Candle (Cork/Irish tradition) and we have a few minutes of family reflection on the season, the year just gone, the highs and lows, and remembering people no longer with us and say a couple of prayers for those and for Christmas.
DD then gets out the Christmas hamper box (new PJs for all, her stocking, her plastic plate and glass for Santa snack, the family copy of "Twas the night before Christmas" for bedtime, naice hot choc for all, and Lush festive bath bombs for DD and I). She lays out the stocking and snack, and then heads off to use her bomb immediately and get into lovely new cosy PJs. Comes back down for her hot choc (and usually a spare cookie!), and then snuggles up in bed with one of us reading the book (we've read it every Christmas since she was almost 1, and at almost 12, she has already asked that we do it this year! She gets very few bedtime stories anymore).
DH and I go back down to finish tidying up and relax for a while, before taking a relatively early night to let Santa get in and do his magic.