1952 2D WILDING OVERPRINTED 'SPECIMEN' TYPE 30 ON COVER USED BY THE POST OFFICE TO DEMONSTRATE CANCELLING MACHINES. Envelope (130 x 78) with a fictitious address in York with 2d Wilding with 'SPECIMEN' type 30 overprint in black. This envelope was used by the Post Office to demonstrate cancelling machines for the public. Rare and not seen by us before. BPA cert 78239. Ex Bodily and Marcus Samuel collections. (Ref 118793).