Lot 65180 – 1921-1932 3c slate-gray, variety watermark sideways,

1921-1932 3c slate-grey, variety watermark sideways, block of four from lower right corner of upper right pane, with part inter-pane margin at foot, unmounted with full original gum; an extremely attractive block that leaves the watermark variety clearly visible in the right margin from the front, with some toning to gum, (SG £1700 for single stamp): mounted on SG stock card with the note « a major keyplate variety. We have handled no other examples (even singles) in the past 30 years, and no other block is known to us. »; cert. BPA (2011).