Mme LeMarchand and her daughters are keen on the Philippa Gregory book too (and much of her work), and also recommend Nora Lofts' 'The Lute Player' and Anya Seton's 'Katherine'.
Not strictly "historical", but loosely based on parts of British history, (Plantagenet era? - sorry, I'm not the history buff in the family) I'd recommend the "A Song of Ice and Fire" series by George R, R. Martin. It's ostensibly a fantasy novel, and does feature the odd bit of magic and the occasional dragon, but it's much more concerned with the feuding and courtly intrigues between the characters. It's occasionally described as 'The Tudors' meets 'Lord of the Rings'. Warning - some strong language, sex and violence. Don't get too attached to any of the characters, either.