South Africa 1913 KGV 10/- Rare Inverted Watermark F/U

1913-24 KGV 10/- deep blue & olive-green INVERTED WATERMARK (SG 16w). An F/U example of this important stamp. Strong cds (likely the base of a Port Elizabeth postmark from whence the known examples emanate), fresh bright colour, unaffected by soiling or creasing as per most others of the less than 10 recorded copies. A rarity. (cv£2000). See additional images, including of the inverted watermark scanned under benzine.