I found High Society in the Regency Period 1788 - 1830 by Venetia Murray very useful, and often refer to it.
"A delightful book well-researched and highly entertaining." Christopher Hibbert."
"Spanning the years from the French revolution to the Age of Reform, the elegant, dissolute Regency era was one of glorious paradox and turbulent change. Drawing on original material from the Royal Archives at Windsor and the Chatsworth Archives, as well as diaries, letters, memoirs and menus covering the whole spectrum of society..."