Ron, simple way to find something close to your accommodation is to use the Google Maps satellite view.
Put in the address of your hotel and then search for pubs and restaurants nearby.
Then check their websites. For example:
Seems a Nicholson’s pub The Porcupine On Charing Cross Road ( depending on the location of your hotel a 10-25 minute stroll) is offering a Christmas Lunch.
https://www.nicholsonspubs.co.uk/restaurants/london/theporcupineleicestersquarelondon/christmas#
Enjoy the solitude on Christmas Day. If weather permits good time to stroll along the Thames or into and around St James Park or further afield, Hyde Park.
If early risers the Peter Pan Cup race at the Lido in Hyde Park is silly fun.