Snaps asked:
"Hello, found a flat button with this backmark, an only reference on the Web brought me to a London gun manufacture- were they briefly in the button business?"
Amost certainly not. According to the best book on button manufacturers and backmarks, the vast majority of button backmarks tell the name of a clothing store or a tailor or other business... NOT the name of the button's maker. There are many hundreds of names in button backmarks (such as Hyde & Goodrich, New Orleans) but there were far fewer button manufacturers.
If you were willing to pay a button maker an additional price, he would put your company's name in the backmark, rather than the maker's name. (For example, we know the Scovill Manufacturing Company was the actual maker of all the Hyde-&-Goodrich-backmark buttons. Such backmarks were called "custom" backmarks, and were viewed by the customer as a form of advertizing. You can see why a tailor or clothing-store would purchase such buttons for the clothing he made, or sold. A famous example of that is civil war US Military buttons with the backmark "Brooks Brothers / New York."