Just finished The Bent Twig (following Cestina's recommendation)- I enjoyed it; reminded me a bit of The Ragged Trouser'd Philanthropists in its ideas, but dressed up in far more congenial surroundings (I'm so shallow
I really liked the ambiguity - there were different ways you could look at almost all of the characters, especially Sylvia. I feel it's sending me off to read some Henry James.
It did feel quite long, although I was reading it on Kindle so don't know how many pages it had.
ETA I thought Belinda in Concerning Belinda (also recommended above) went through life a little like a chaste (but dimpling) Barbarella. Be interesting to know what anyone else thought.