Canterbury

This is now your 3rd post about your Christmas - New Years sojourn in the UK.
I have to inquire if you've done any research on how you will be traveling? Train? Car? Bus?

I ask because trains will be packed and unless you've reserved in advance tickets will be very costly.

On Christmas day there will be no public transport. No trains, underground or buses. Might be some Uber drivers or Black cabs but costs will be very high.

If you plan to have Christmas dinner best to reserve now and find a place close to where you will be staying and be prepared to walk.

Christmas in London is about being with family. The city shuts down!

As far as finding out about restaurants I encourage you to use Timeout on line. For instance:
https://www.timeout.com/london/food-drink/london-restaurants-open-on-christmas-day

This link for a 2017 article about the top 10 restaurants in Canterbury might prove helpful:
https://theculturetrip.com/europe/united-kingdom/england/articles/eating-out-in-canterbury-the-10-best-restaurants/

I always research local food blogs for restaurants when I travel.
http://londonstreetfoodie.co.uk

https://notsobasiclondon.com/category/monthly-food-finds/
http://www.thecuriouspear.com/city-guides

And since you will be there during the Holidays I encourage you to see a panto (Pantomime) which is a Christmas tradition. Something like this one: https://www.visitlondon.com/things-to-do/event/47823975-cinderella-at-churchill-theatre

Be sure to wander about the free Hyde Park Winter Wonderland, (if seeking a drink there's a merry go round with a bar and a huge beer garden), it's especially gorgeous at night time because of the lights.

Or ice skate at the Natural History Museums rink. To see an unusual department store check out Liberty. Stroll past Selfridge's Christmas window displays and if staying anywhere close to Hyde Park take in the traditional Peter Pan Cup race in the Serpentine on Christmas morning. https://www.visitlondon.com/things-to-do/event/10716901-peter-pan-cup

https://www.timeout.com/london/things-to-do/southbank-centre-winter-festival-guide

Loads to see and do in London just be prepared for the quiet on Christmas day and the insanity of the after Christmas sales.

Cheers!

Thank you for the information!

Where are you staying in Canterbury? You'll have lots of choices on the High Street if you are in that area. It may also depend on what day you are there as to what is open.