Great Britain 1950-52 21/2d pale scarlet. (New colours, Wmk upright). SG507varGreat Britain 1950 52 21 2d pale scarlet. (New colours, Wmk upright). SG507var Very fine unmounted o. g imperforate left hand marginal block of six imprimaturs, showing Cylinder L20 Dot from the endways coil printing with "BPMA" handstamps on reverse, some gum disturbance confined to sheet margin from original mounting of sheet by post office, nevertheless a unique positional piece. ALERT ME WHEN ANOTHER IS AVAILABLE > SELL ONE OF THESE >