Christmas advice please as we are struggling to come up with a plan and need to book flights

London is really lovely at that time, even Dec 24, 25, and 26. Some taxis still run, walking is a delight without all of the traffic, and there's a lot of London to enjoy by walking. London Walks offers tours every day and movie theatres are open. We enjiyed that one Dec 25 evening as we might have done at home. See if you can find yge book "24 Great Walks in London." It is no longer in print but available used with goog good itineraries not requiring sites to be open.

I spent the last two Christmases in the UK. The first year in London, this past year in Manchester.

Everything shuts down. Except for a few restaurants, just about everything else will be closed. If you want to stay outside a city, it would be best to book a hotel with a restaurant because they will be serving on Christmas. If headed to a city, there will be open restaurants. Just remember that public transportation will not operate.

Remember, that time of year is the beginning of winter. Do you really want to hike.

Also remember, days are short. In the UK, the sun will rise between 8:30 and 9:00 AM and set around 3:30. Short days.

For time out of England I'd consider flying to Seville for (likely) much better weather. However, I suspect that option is also attractive to a fair number of English folks, so flights may not be especially cheap. And I have not researched opening hours of the key sights over the holidays. (I realize that for you, Seville may be old news.)

This suggestion brought to you by someone who hates cold, damp weather and days with little sunlight. YMMV.

I have spent several Christmases in London and one in York. On Christmas Eve pubs have always been open and prereserve a Christmas roast for Christmas Day. Do some research ahead of time to see if you can find a live ...what is it called...Carols of Christmas, etc. You are only talking about one day to be creative to entertain yourself. If you are not a shopper on Boxing Day, go to the movies. FYI, my last Xmas visit was 2012, but I doubt this holiday has changed.

Christmas isn't a bad time for hiking, it's typically overcast and around 10c in the South. Boxing day is a tradional day for going on a long walk to dust off the cobwebs and try to burn off some of the excess calories.

Snow is rare for much of the UK at this time so consider it either cool and damp or bright and crisp.

A cottage rental would be a good option, prefarably one close to a pub. You can enjoy walking then visit the pub during its limited hours before returning to the cottage and tucking into the provisions you bought beforehand in front of a roaring fire. Who could want for more?

Seville would be warmer than London, but it’s average December rainfall is significantly higher than London! Hiking anywhere in mainland Europe could be hit or miss in late December.

Airfares anywhere are going to rocket in price as soon as school holidays start - 16 to 20 December 2020 for the U.K. Staying in the UK and taking the train to York or Edinburgh would be an option. Lisbon in Portugal another, which would be milder.

Spent Christmas 2019 outside London in the Richmond suburb. Stayed at the Premiere Inn on Mortlake Road. Within in walking distance is a huge Sainsbury market so I bought “ snacks “ for Christmas. There’s also a tiny independent market across the road which was open on Christmas Day, J Food and Wine. Stopped there for bottled water and to satisfy my sweet tooth with a Snickers candy bar.

The hotel’s in house restaurant was open and serving on Christmas Day. Room had a comfortable double bed, cable TV, free wifi, good supply of hot water and the price was right for my week long stay.

Out early and spent Christmas Day strolling in and around Richmond Park to the Thames River path then up Richmond’s main drag. Perfect Christmas Day for me and my camera.

Chose to stay in the “burbs” because I’ve been in London proper for 4 or 5 Christmas’s on prior trips.
Wanted and enjoyed the different experience.

There’s a traditional pub, The Crown, nearly next door. Perfect for a pint after long days of meandering. Kew Gardens within walking distance. I could see the Pagoda at Kew from my room’s window.

Richmond proper had great coffee spots ( Butter Beans my preferred spot). It is next to the Richmond Train Station and Underground.

Lots of shops, cafes, restaurants, pubs and is about an easy all within a 10 block stroll from the Premiere Inn. Enjoyed a tasty leek soup and pint at the pleasant albeit small Angel and Crown pub. Stumbled upon it after I’d explored the Mary Magdalene church grounds.

As I’ve said in countless London posts I wander and roam while there. This enables finding off the beaten path places to enjoy. Places that make me smile. Places like the Angel and Crown or Petersham Nursery Tea House or Richmond Hill Bakery..

Lastly as the OP mentioned hiking I can say Richmond Park is huge. I found it most enjoyable. Entered under tree lined canopies off Sheen Road and then strolled along easy paths ( shoes got muddy) to the Ham House and then along the River path. This wasn’t a planned route. Just happened. Not really hiking but a good long and tiring walk.

If I were to stay again in Richmond I would absolutely return to that Premiere Inn.

We don't give each other much in the way of gifts and instead take a trip every Dec. London was our favorite. Christmas Day was the "vacation from your vacation" where we ate in hotel restaurant and otherwise did nothing. If you want to go to a Christmas service at Westminster Abbey, I recommend the one on the 23rd because transportation is running. You must reserve far in advance-check the website and sit by the phone on the day they begin taking reservations. With a daughter, Boxing Day was no problem-we told her that was the only shopping day, so didn't waste time shopping on days when we could sightsee.

Christmas season in London is one of our favorites. We stay near Trafalgar Square with the tube (Charing Cross) and bus lines making it easy to get to more distant sights like the Royal Albert hall for their spectacular Christmas programs. Some of the buses travel down the most famous Cjristmas-lighted streets on the way to Harrod's. We've stayed at Citidines Trafalgar Square and Club Quarters Trafalgar Square and for a return to college days, we once booked through the London School Of Economics a dorm room at Northumberland House, which is next door to Club Quarters. Other Christmas offerings are at other venues. We booked one at St.-Martin-in-the-Fields and ate at their Cafe in the Crypts several times. We walked to most sights -- Covent Gardens, Buckingham palace, South Bank, St. Pauls, Westminster Abbey, and the theater district. Don't miss the Royal Albert offerings and book them early as they always sell out. Same with other Christmas programs. Good luck. Send me a private message if you need more tips about hotels, where to eat, and what to visit off the beaten path.