Not an 8br but go to
http://shotgunworld.com/ and do a search. Might want to ask there if you haven't done so already. Those boys do get out more.
If they don't respond to your post, and the only reference you find is from paperback book with a yellow cover (you know Walt is not a particularly common name in Spagetti Land) you're probably chasing a ghost gun!
PS. I have not visited them in few years, but another good place is Wildfowler Magazine BBS. The English still use 'single handed punt' guns on the marsh.
