South Africa Postage Due 1969 4c Wmk RSA, Afrikaans at Top

POSTAGE DUES: 1969 4c deep myrtle-green & emerald, WATERMARK RSA, AFRIKAANS AT TOP (SG D62c). Superb UM top marginal part-arrow block of four. A rarity of the South African Postage Due issues. Photo-cert: Eichele BPB "A rare printing more so in a block." (cv£1500+). See additional image and of certificate below.