Keep in mind that the UK, Birmingham especially, was a "trade." Most/all manufacturing shops were headed by a master gunmaker. Every master knew how to get out a "best" gun. If he didn't have all needed skills in-house, he most surely knew where to get the work done by out-workers. So, a " best work" gun can show up with anyone's name on it. The issue never was about designs, materials, or skills. It was always about getting the commissions to build such guns. Some names were more successful than others in attracting "best work" commissions.
