Thanks very much for your thoughtful and thought-provoking response. I appreciate it. It makes a difference to my pleasure in reading you to understand your reasoning and your choices regarding the characters. And your point about Austen's limited experience of love and male-female interaction is well taken.
In fact, I have read enough biography and other non-fiction about the periods you refer to see your points. And I too live in Europe... However, it is indeed the very fact that Lizzy is not a member of the upper classes, that her virtue is as much or more her ticket to a comfortable future as her looks and wits, that makes me think she would be more uncomfortable. Byron and Lady Lamb are light years away from her.
But then again, you do a good job with Brougham pointing out to Darcy that SHE can't move the relationship along, so, yes, the reader can see that her only recourse might indeed be these little symbols of her willingness for more. I guess I didn't give you enough credit.
I must tell you that my initial message was really a compliment! Of all the PP sequels, spin-offs, pastiches, and alternative storylines that I have read, this is the only time I have made a comment to the authors. Other than Pamela Aidan's trilogy, there are very, very few that seem to me to be well done (or even worthy of real interest). So it was perhaps a back-handed compliment, but one nonetheless.

So now, just another comment : If your Darcy is really that carefully daring, and aware of the transgressions that she is allowing him, he is indeed being quite silly, or rather "blind and insecure" as you put it. He even loses some of his attraction for me ;-)

Kind regards and many thanks for your response, Kate

P.S. Another slight disappointment is that Darcy seems to have completely forgot his loving sister. And to think, he was such the letter-writer ! :-)