Here's the thing about most Golden Age mysteries: the puzzle is all. No matter how witty or clever or brilliant the writing is, it's almost never about the characters themselves, but about the murder mystery puzzle. Which is, of course, why I read mysteries; I love the puzzle and I love trying to solve it. But unfortunately, if the reader does solve the murder/puzzle, there's not a lot of characterisation to fall back on; solve the puzzle and the remaining story can be tedious.
I solved this one on page 88-89. I don't think I did anything particularly clever, just that a certain passage hit me a certain way and it all became clear to me. The only thing I ended up getting wrong was the relation of the murderer to one of the characters and then only because I imagined the murderer to be the wrong age.
I didn't dnf, or skip to the end to see if I was correct solely because, when Heyer is 'on' with her writing she is on, and this is one of her better writing efforts, even if the plotting went astray (and I've found out her mysteries were all plotted by her husband). The story behind the mystery plot is a farce and Heyer thoroughly caricatures everyone except Hannasyde. The dialog was electric and even though I was thoroughly impatient with Neville at the start, I thought him wildly entertaining by the end. I wanted to keep reading just to see what he'd say and do next.
So, 2 stars for the plotting because... page 89. There was never any doubt on my part that I was wrong. But an extra star because the characters are Heyer at her wittiest and most hilarious.