I find that really good historical fiction is pretty rare... One author I really like is Jean Plaidy, whose historical fiction is well researched and well written and she doesn't tend to "fantisize" too much. She wrote a whole slew of serial historical fiction about the Tudors and all very good. Unfortunately, often her books end up with romance novel - like covers, which is too bad because what's inside is very good quaility stuff. But I don't think the author has too much control over what's on the cover. Besides, she is dead. But she did write a lot about a whole slew of British royalty, strating with the Platangenets and ending with the Hanoverians... Highly recommended.
Another one I really like is Edward Rutherfurd, even though he doesn't write about royalty specifically but more like epic history, royalty pops up once in a while, the rest of the characters are fictional but wonderfully developed! His best two, IMO, are London and Russka. London covers the Tudor era of course, among other eras, and Henry VIII and Elizabeth and Mary, make cameo appearances... Good stuff.
Sorry, PL, I didn't read those two books you mention.