South Africa 1927 London 4d Progressive Die Proof

1927 London Pictorials 4d Native Kraal (SG 35b): Bradbury Wilkinson PROGRESSIVE DIE PROOF taken in deep dark (chocolate) brown sunken on wove paper. The proof with blank cleared fields for the country name at top and "postage" at base. Marked in pencil manuscript "OK" with initials. A rare & exceptional proof in intermediate state.