Today's update from Anne-Marie brought a very positive rejection:
"very impressed with the fluency of the writing ... there's a huge amount of potential here for his career as a writer"but a rejection nonetheless. Anne-Marie also alerted me to news in the Bookseller that Harper Collins had just picked up a first novel about a search for treasure buried with Alexander the Great. Its title: The Alexander Cipher.
So it looks like I will need to find a new title sooner rather than later - and certainly before Lord Alexander's Cipher; or, the Bridekirk Behemoth is submitted to Harper Collins.