South Africa 1913 KGV 1d Plate Block Inverted Watermark etc

1913 KGV 1d rose-red PLATE 3 (SG 4w var). VF/UM upper left corner block of four varieties INVERTED WMK & BROKEN HORN IN WMK V18 top left corner stamp. Perf support top margin, previously hinged in top margin only. Excellent block. (cvR1900+).