W. Thorn was a gunsmith from 1874 to 1876 at 4 Pall Mall. I don't think he was connected with the H. A. A. Thorn connected with Charles Lancaster, but I could be wrong. I would post a picture, but the pistol is at my brother's house. I have gone through English gun books that I have and can find no reference to an L & S barrel maker. Thanks for all your help. There were a lot of provincial outsource makers.