Lot 30389 – 1929 10s Seahorse experimental plate proof, imperforate block of four of the rolled impression with outer frame lines incomplete

1929 10s Seahorse experimental plate proof, imperforate block of four of the rolled impression with outer frame lines incomplete, printed in black on thick wove card at the Royal mint as an experiment into alternative methods of plate production, rare, only four sheets of nine discovered (See SG Spec. Vo.2 p.180, £32’000+)