Mike is absolutely right about the British commercial proofs. Any firearm sold commercially had to go through one of the British proof houses (London or Birmingham). A good case in point is all the firearms Lend-Leased to Englandicon. Unless they were marked with the British broad-arrow property mark, they were not marked at all until they were released by the government for commercial sale. The requirement for NOT ENGLISH MAKE was dropped from the Proof Act of 1955. Even British military rifles released for commercial sale had to go through the proof house.