Toby, according to the information I have, Birmingham went to a different date code mark, having dropped the crossed swords mark in 1941 and replacing it with a circle divided into three, year letter on the left, starting in 1950. That was replaced with an undivided circle beginning in 1974. I've seen the 3-part circle date code but not the undivided circle. Have they now dropped the circle and returned to the old crossed swords mark, but with year numbers rather than a letter code? I have a partial list of the new proofmarks (including STD over a crown) that first appeared in 2005, but the Birmingham date code mark isn't shown. Thanks.
