Looking for an old post-P&P story

The story is about Lizzy's first dinner party in London where Darcy's uncle and aunt, the Earl and Countess, and the Gardiners are guests. The earl is initially quite offended at Mr. Gardiner's very affectionate conduct toward Lizzy, thinking him way above his station. By the end of the evening, Lizzy has charmed the earl who also accepts the Gardiners.

This story is not new. Anyone?