DD used to come into my office with me, as I had to turn up for an hour or lose a day's leave, most people brought their DCs. DH would travel with us but go for a quiet coffee locally, and meet us about 11am or so. We'd go buy DD's birthday cake (and anything else we saw that we fancied) in M&S (main rush for pre-orders was gone, and really the city centre one empties out quite early on 24th). Then we'd go for lunch together before heading home (maybe going for a last visit to the "Living Crib" outside the Lord Mayor's house on the way back to the car).
At home, DH and I would prep the potatoes, veg and stuffing for turkey dinner, just mooching around the kitchen together. DD and I would bake cookies for Santa (sometimes from scratch, sometimes just "slice and bake" from a half batch I always make sure to freeze in Nov/early Dec, just in case we don't have the time/energy on 24th).
Dinner on 24th is always a "platter" dinner - cold buffet of things in the middle of the table for everyone to help themselves. Smoked salmon, prawns, squid rings, cured and cooked meats, cheese, cherry tomatoes, carrot sticks, pepper sticks, lettuce, hummus, pate, crackers or breadsticks, olives, …..etc.
After dinner, we head into the sitting room where we only have low level lighting (maybe the tree lights and 1 side lamp) rather than bright lights, and the youngest in the household lights the Christmas Candle - an Irish tradition to show there is room in our Inn for any weary travelers in need. Ours goes on the mantlepiece rather than the window. In our house, we take a few minutes to remember the good and bad that have happened during the year, and also to remember family members no longer with us, which is a lovely quiet time of reflection for us together. We say a single prayer (growing up, it was a decade of the rosary).
Then we get out the Christmas Eve Hamper that I have put together (and everyone knows it was me). New PJs for everyone, festive bath bomb each for DD and I, hot chocholate for all and a Christmas beer for DH, and our copy of "Twas the night before Christmas", DD's Christmas patterned plastic plate and glass (for Santa's treat), her stocking and her snowman covered hot water bottle.
DD then sets up for Santa, cookies, milk and a carrot.
She heads up for her bath and gets into new PJs, before having hot chocolate snuggled on the couch, and going up to bed with her cosy hot water bottle where I still read TTNBC in bed (even aged 13 last year, it was requested!).
Christmas Day, we get up and she opens her stocking in the sitting room while we organize ourselves with a coffee, and we all work on making a nice but simple breakfast (usually we bake pastries - JusRol or M&S frozen ones; squeeze a couple of oranges, and make a large jug of coffee, maybe adding some fresh fruit to the table as well).
Out to mass - usually 11am or so (we have a few options locally) and then a few visits to extended family relatively locally (drinks and nibbles) before getting home about 2pm or so (or calling in home en route to the last) to put the turkey on. We are generally at home fully before 4pm. We spend about 20-30 minutes once we get indoors to light the fire, throw a tray of M&S nibbles in the oven, get the potatoes going, and anything else that needs to be done, open a bottle of wine and a nice drink for DD, and then go into the sitting room with a drink and snacks, to start opening presents. It can take a while as we don't rush this, enjoying the quieter time together. We may need to pause for a few minutes to do something in the kitchen or top up glasses.
By the time we're finished, dinner is almost there, so we need to do a few more things like putting on vegetables, but we get another chance to sit and relax together while DD plays before we actually eat.
By the time we've finished eating and tidying up, we generally just relax on the couch for an hour or 2 before falling into bed, for a good sleep. (We also have DD's birthday on 26th, which means hosting others, so we enjoy that peaceful oasis on 25th).
We also spent some years visiting family for Christmas - usually staying in a SC cottage locally and going between both sets of DPs, with 1 serving turkey in the middle of the day (their family tradition) and the other serving turkey for the evening meal (their family tradition) - both always say they know we will eat later/have eaten earlier, so there's "no need" to have a full dinner with them, but they still pile the plates high!! Hence the need for independent places to stay, and why we don't go down every year!!