1945. 2 registered postcard issued for the phila stamps exhibition in 4/1945 bearing a complete set of the pictorials including 500m & 1 pound(except 90m), actually gone through the mail as indicated by the blue crayon cross, and the messages on back. of philatelic origin as is everything ever prepared in a philatelic exhibition, but how many times have you come across 500m & 1 [pound actually gone through the mail.
