Welcome to the forum. I can't identify the manufacturer. Just thought I'd add some information. I have a Dutch pipe with a brass ring with your mark. http://i40.tinypic.com/4v1vyu.jpg Since your Stanwell is Danish I think we might be looking for a European or Scandinavian manufacturer. Pat.
Welcome to the forum. I think you did the best you could on the pictures with what you had to work with. Eloi Pernet. http://i109.photobucket.com/albums/n80/2209patrick/PernetParis.jpg Couteau ouvert is the symbol in the middle of the mark and means "open knife". http://eloi.net/" onclick=...