Best of London in 7 Days for New Years Eve

leaving any winter covid considerations aside, my only concerns would be the shortest days of the year (sunrise well after 8 and dark by 3:30 to 4, and if it rains all lights on an hour or two before that) and the lack of transport just before and after your tour.

You mean the one that starts on Boxing Day and ends after breakfast on New Years Day? If so, transport and the rest of London starts winding down in the afternoon of Christmas Eve and completely shuts down on Christmas. You will find no tubes and very very few buses in London on Christmas; only a very few usually ethnic restaurants or a few pubs and no shops open, and no trains on Christmas or Boxing Day, and only a very light schedule (unless holiday engineering works shuts certain lines completely) for the full week until New Years Day.

The tour will arrange transport for what you are doing during the week though, and will possibly have a plan for New Years Eve. It could be a very good time.

Just be careful just before and just after... New Years Day being a Sunday, even less than normal will run.

I've never taken a Rick Steves tour although I'd like to one day, but I do live near London and spent many years working for railroads into London.

I spent this past New Year's Eve in London. It was my second. (But neither on a tour.)

If you plan to arrive on Christmas Day, you will have to arrange private transportation from the airport to your hotel as no public transit will be available. You should be okay during the week.

If you arrive before Xmas, make sure you make reservations for Christmas Day meals. Few places are open that don't require reservations. (The KFC was open near me as were the pubs. Pubs required reservations. KFC didn't. (LOL)

This past Xmas/New Year's week didnt seem as crowded as in the past. I have a feeling this year's holiday week--barring any unforseen viruses--will be back to normal.