Die number for SG54;
1
(WW1 is embossed at the base of the neck)
The WW stands for William Wyon, the engraver. These letters and numbers can be faint or even invisible.
William Wyon by William Brockedon, in pencil and chalk, 1825
William Wyon engraved the head of Queen Victoria at the starting when she was 13 and finished when she was 18. His engraving was used on the line-engraved postage stamps of 1840–79, beginning with the Penny Black, the embossed stamps of 1847–54 and the postal stationery 1841–1901. His design also influenced the surface-printed stamps first printed in 1855
The die for the embossed stamps was engraved by William Wyon, and based on his Wyon City Medal of 1834 which depicted a fifteen-year-old Victoria
1847 Postal Notice from the G.P.O. in Dublin dated September 1847 - relating to the issue of the new 1/- stamps bearing a horizontal pair of SG55