Proof Block Larger Than four 3d. black and brown, an imperforate plate proof block of six (3x2) on gummed watermarked paper; two small thins at foot otherwise fine. Very rare. Photo

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Proof Block Larger Than four 3d. black and brown, an imperforate plate proof block of six (3x2) on gummed watermarked paper; two small thins at foot otherwise fine. Very rare. Photo