The London Ladies by Georgina Grey

I actually read this book a few weeks ago and can't really remember too much about it. I think I found it vaguely irritating but I can't recall why.

They looked like sister and brother with their golden good looks and charming manners.

But they were not. In fact, they were adversaries. Evelina had caught the eye of David's uncle-a dashing old rue'-and David was certain that the young woman was up to no good.

Evelina, horrified that anyone could think she would encourage the advances of old Lord Beemish, was furious with David.

But it was that old rogue himself who finally thought up a solution to this strange triangle.