Great Britain. (Used In Ireland). 1873. Registered envelope addressed to France bearing SG 123, 6d pale buff (plate 12) tied by '186' in diamond with adjacent 'Dublin/ Registered' and framed hand-struck 'R' , routed via London with oval 'Registered/ London' and circular 'PD' with French entry cachet and Nantes arrival on reverse. Superb use of the rare Plate 12 used on registered mail from Ireland.