1927-30 £1 pale olive-green & red (SG 57/CC92). PLATE NO1 CONTROL BLOCK OF FOUR, VF/UM from top right corner, previously mounted in margins only. A most elusive plate block, few of the possible 200 control pairs ever existing (from the printing of only 50 sheets) survive. Photo-cert: BPA. (cvR43000+). See additional image and of certificate below.