The first appearance of THE LADY OF BLOSSHOLME was as a serialized novel, published in The British Weekly, June 24, 1909 through November 18, 1909, without illustrations.
McKay, Scott, and Whatmore claim that Hodder and Stoughton published the first edition in book-form in London on December 15, 1909. Apparently 15,000 copies were printed, with 5 color illustrations by W. Paget. There are no ads at the end of the book.
According to Whatmore:
In January 1909, 100 proof copies were printed.
In April 1909, 12 pulls of the corrected version of the proofs were sent to Hodder and Stoughton and 2 to HRH.
Higgins claims that The British Weekly paid £750 ($127,000 in 2020 dollars) for the serial rights, and Hodder paid £750 ($127,000 in 2020 dollars) as an advance for publication in book-form.
This novel was not published in the United States of America.
See the VisualHaggard.org page dedicated to the illustrations found in various editions.
According to Sumner and Stillman, booksellers out of Maine, from whom I purchased this copy: "Mrs Sarah Pitt was a writer of novels meant for children, or at least young adults -- for whom Cassell was likewise the UK publisher; she had been quite popular during the years 1881-1900."
I am not certain that they are correct, but their theory sounds reasonable.