Mrs Dalloway (Virginia Woolf)
Anything by PG Wodehouse or Nancy Mitford, or the edited Mitford sisters' letters
Vile Bodies or A Handful of Dust by Evelyn Waugh
The Mapp and Lucia series by EF Benson
Dorothy L Sayers murders: the Wimsey/Vane courtship and honeymoon ones would probably suit your mood (Strong Poison, Have his Carcass, Gaudy Night and Busman's Honeymoon)
Or return to childhood and try the Flambards series.