"Eric 375," because of the presence of Birmingham proofs, the guns could have been sourced from either W & C Scott or Isaac Hollis & Son. Like Scott, Hollis was another known source for hammer-gun actions and barreled actions prior to Georg Lindner's earliest involvement with the importer, Schoverling, Daly & Gales.
But because Schoverling, Daly & Gales almost exclusively sourced W & C Scott in the 1860's and early 1870's for its Charles Daly hammer-guns prior to its contact and subsequent sourcing agreement with Prussian master gunmaker Georg Lindner, which was prior to son Heinrich's succession to the business later in the decade, and because not much in terms of the importation of firearms from overseas occurred without this major New York importer's / retailer's / wholesaler's involvement for much of the last quarter of the nineteenth century, my opinion is that the subject hammer-guns were sourced from W & C Scott, or at least their components.
Given the end user's skills, such as those demonstrably possessed by Abbey, Schafer or Donn for example, proprietary or inventive alternations could be made once imported constituents parts were acquired and ready for assembly, if not already fully assembled or even completely finished and ready to retail when arrived. Alterations could include the addition of side-levers or thumb releases on the Purdey-patented pattern.
Regards,
Edwardian
