What intrigues me is that the subject of Lady Kate is very much typical of Hill. Per Amazon UK (Waterstone's doesn't have a description) it's about Lady Katherine Gordon, wife of Perkin Warbeck and several other men besides - I don't know much about her later life. Unfortunately, the Tudor lady on the jacket art appears to be sporting a five o'clock shadow.
Even curiouser, Fantastic Fiction not only has Lady Kate grouped with older Hill novels, but it lists several newer ones too, mostly from United Writers. One is about Shakespeare's supposed journeys in Scotland, which is also in keeping with her usual subjects. I wonder why she's not with Robert Hale any longer, and why I hadn't heard about these additional novels before.
Has anyone else read her? Many of her older novels were published in the USA. And you can read more here (from a previous blog entry) about her novel Countess Isabel.