D" on 2d. purple-brown, a used single, fine. B.P.A. Certificate (1950). S.G. 115, £700. Photo" /> used 1928 (Feb.) "2½<SUP>D</SUP>" on 2d. purple-brown, a used single, fine. B.P.A. Certificate (1950). S.G. 115, £700. Photo | Christie's