Thanks for this post Bob, it was a very interesting read, especially the history behind the Louis XIV 24-pdr bronze naval gun.
I'm guessing that the Holland & Holland mentioned as the previous owners of the cannon, is the famous custom firearms making firm. I had a chuckle reading that when they were test firing the cannon they couldn't take the powder charge up to what they thought would be an historically accurate measure because they were conducting the firing in a residential area.