An extremely rare engraved steel progressive die plate for a Portsmouth Memorial poster stamp 1914-1918, probably by Bradbury Wilkinson, height 8cm, width 10.1cm (some sticky residue to surface, a small amount of environmental damage to edges, some rust patches). Note: it is thought that these stamps were produced in aid of the memorial charity to erect a monument in the city of Portsmouth, together with a rare late 19th century engraved steel die plate depicting a locomotive, probably American, probably used for the National Banknote Company, New York, height 8.2cm, width 12.7cm, a group of trial prints from the same plate and an early 20th century engraved steel die plate for a stamp-form advertising design, detailed 'Bradbury, Wilkinson & Co. Ltd.', with portrait of a bearded man, value '3' to top corner, the reverse of the plate stamped 'John Sellers & Sons, Sheffield, England', height 7.6cm, width 6.5cm.