Christine Leslie wrote Four Start a Riding Club, illustrated by Anne Bullen. It is the last fictional title Anne Bullen illustrated. The book is not the most scintillating of reads, but the illustrations are classic Anne Bullen.
Finding the book
Four Start a Riding Club is extremely hard to find. I have to say it is really not worth paying epic sums of money for unless you are dead set on completing your Anne Bullen collection.