In the summer of 2022, my family was in London for Queen Elizabeth’s Platinum Jubilee. I caught COVID on the back end of the trip, and the rules then required ten clear days before I could fly — so my family went home on schedule and I didn’t (I know, ten days alone in the Mayfair section of London; life can be hard). Sick for a day, maybe a day and a half. Then I had the city to myself, and a London that, unlike the America at that time, had de…