Afraid my page won't help a lot with further decyphering. All the guns on my page are A&D 12ga ejectors, marked either "Southgate" or "crossbolt". (Mine are crossbolt guns.) And all but two were finished by Webley & Scott. The other two carry an abbreviation that appears to be "Sdrs". My guns do indeed have the W&S maker's number on the barrels (forend loop), as indicated on the A&N record sheet. Interestingly, however, only about half the W&S guns on the page show anything in the "Barrel or Maker's No." category.