SG 59 1854
Scan courtesy Mike Holt
The 6d has no 'silk' threads in the paper.
The design is based on the
Wyon City Medal -
1837,
primary die engraved by William Wyon (1795-1851).
As the stamp was issued after his death it does not have his initials engraved
on it
Printed in two panes of 20 (5x4) 1s shown
Image source British Postal Museum from the R M Phillips Collection. Vol XXX Pg 16