Sutcliff wrote a fascinating autobiography (?called something like Blue Remembered Hills?). She had childhood rheumatoid arthritis and was, I think, a wheechair user for most of her life. There was a prospect of marriage at one point but too much family pressure (as I recollect, from both sides), about marriage for a 'cripple' (shades of Cousin Helen in the Katy books).

Sutcliff, like Renault, I suspect was strongly influenced by Naomi Mitchison's revisioning of the historical novel in the 20s and 30s, but pretty much losing her feminism and leftwing politics (which are, I may add, very well-integrated into her works). Mitchison wrote a lot of children's books, mainly historicals, but I think they're all out of print now. Mitchison was so much less about 'women couldn't do heroic stuff in those past days' and more about 'in what ways could women be heroic in those circumstances'.