PL.2 MATCHED PAIR LETTERED PH BOTH S.C.16 (SG21) ONE WITH INVERTED WATERMARK. Good to fine used 1855 die 2 1d pl.2 lettered PH S.C.16 WATERMARK INVERTED (SG21Wi) centred slightly to left but no faults and cancelled "186" Irish numeral of Dublin. Matched with example same plate, same lettering, also S.C.16 (SG21) but watermark upright. Latter centred slightly low and cancelled London "16" Inland numeral. A most unusual and rare matched pair. (Ref 105558).