Well, I've just spoken to Margaret. What a nice lady. Many thanks for your pointer. And thankyou others for your responses.
Yesterday I went on a pilgrimage, inspired by Tom Rolt's "Narrow Boat". To Napton, including a very good lunch at "The Folly", and Braunston. I was surprised by how many boats were moored and locking, and by how many had painted cans and other articles. I enjoyed helping people through the locks. I must have a painted can. Margaret, I'll be in touch.
It is sad in a way that the "Bull and Butcher" name was lost to Napton. But the building survives and there is a photo of the original by the bar.
Thanks, again.
Brian