Per my research, the Atkin or other BV2 name (Westley Ricahrds, Dickson, Rigby, Grant , Beesley, Powell, Atkin, Churchill, Henry, Lancaster, Evans, Watson, Wilks, Greener, Boswell, Gibbs, and Lang) will value at 2/3 of the Purdey's (H&H, Boss or Woodward) value for USA retail of a 12 bore SXS of 1890ish to 1960ish vintage.