The original Katherine was by the American Anya Seton, and was a historical novel. It was published in 1954, and came 95th in last years British book reader's poll. This latest one is a history, which I was interested to find because like you Lurker,I loved the original. Lucraft does not seem to have unearthed much more about the life of this lady, who eventually became Duchess of Lancaster, and anceestor of the Tudor,and Stuart lines.
There is a much shorter pamphlet about her(6000 words) by Anthony Goodman, which I haven't got round to reading yet.