18a, 1869 (4d) Dull vermilion, Imperforate, block of four with clear to large margins, large part o.g. with a bit of gum added, faint pressed crease across top stamps, o/w Very Fine, a rare multiple; 2011 Sismondo certificate also stating "...only two pairs have been offered in the auction market..." (Scott $3,000 as pairs; SG 28a, £3,000 as pairs) (Image)