Send a message to the person who requested a photo of the grave monument of Robert Middlemas with the following comment:
My maiden name is Middlemiss. Elizabeth Middlemiss may be my 2x great aunt who was born in London and lived as the wife of a hotel keeper Robert Middlemiss in/near Edinburgh. The birth date is about the correct time.Not sure how I can help but if your work extends to Cambridge, UK then I am happy to 'give it a go'.Penny