South West Africa 1926 KGV £1 VIa Plate No1 Corner Pair UM, Rare

1926 KGV £1 pale olive-green & red, Setting VIa, 9½mm between, "South West" 16½mm long (SG 40a/CC 63a). PLATE NO1 CONTROL CORNER PAIR, Superb fresh UM from top right corner. Prior hinge top margin only. A most elusive piece, few of the possible 100 control pairs ever existing (from the only 25 sheets printed, ie only 25 possible each corner) survive. (cvR165000+). See additional image.