GB 1924 ½d Yellow-green Used, Attributed Wmk 111a with Comparison

Great Britain 1924 George V ½d yellow-green shade, fine used, attributed by the vendor to experimental paper with watermark type W.16 (111a). The attribution is based on closer spacing of the horizontal watermark rows, approximately 12.5mm rather than the normal 14.5mm. A fine used ½d with normal Block Cypher watermark is included for comparison. The vendor notes that Gibbons lists watermark 111a for the 1d and 1½d values only, not the ½d. This example is sold without a certificate; the experimental-paper attribution is not independently certified. Reference supplied: Specialised N33(6) / SG 418 variety.