Thanks again to my wonderful feedbackers. Extended discussions have lead to new insights into the main character (new for me, anyway). Suddenly, she seems more real, and a bit more frightening, actually. Hopefully it comes out in the rewrites, and makes her more interesting to the readers.
Talk of two separate problems (a slow start problem, and a problem with a certain part not being "baroque" enough) lead me into a significant rearrangement of the first part of the book, and an addition which, I think, helps a fair bit with the slow start problem while also helping with the baroqueness. At least, it does mean that somebody gets shot much earlier on. And if there's one thing that helps a book it's gratuitous shootings.
Some other bits are re-crystallizing as well, in new configurations, after being smashed to bits. It's all very exciting.