I have read a Wheel of Fortune, about Richard III but I don't think it was written by her.It was superb
It wasn't about Richard 111, actually. (maybe you are thinking of Sharon K Penman's "Sunne in Splendour", which is a marvellous book)
But the modern (well 18th/19th century) family Howatch portays in Wheel of Fortune has parallels with the Plantagenets, Kester being Richard 11, Harry being Henry lV, Robert being the Black Prince, Ginevra being Joan of Kent etc. It's interesting to find the historical figures in her novels. (Even Katherine Swynford is there as Bronwyn).
I find her books original in their concept, and riveting in their plots- since they are taken from history and adapted to fit modern family sagas. I think "Cashelmara" is the weakest of the 3, but even it is a good read. There are also "The Sins of the Fathers" and its sequel, which retell the relationships of the Roman Caesars again as modern family saga.