Ruth Rendell has been writing novels set on various London blocks in addition to her stand-alones, Inspector Wexford novels and Barbara Vine books.
The latest, The St. Zita Society, has the usual combination of various households but is the first written in "Upstairs, Downstairs" mode. Hexam Place is one of those posh London squares where people still have servants. One of them insists on forming a society of the downstairs folk while they meet at the local pub.
Not much happens at these meetings. There are so many characters that it's best to read as much of the book at once as possible (which you know I can't seem to do these days).
I was about to put this one down as a rare misstep for Rendell, whose work has been creepy good for decades, but an unexpected event midway through has really picked things up. If only Hitchcock was still around to film a version of this.
Now to see if it continues through to the end as well as it's going now.