I acquired this sterling silver boxed single ring set a year or so ago. I believe the hallmarks represent the silversmith Henry Mathews, Birmingham England. Not sure about the date hallmark also the Z hallmark is a mystery. 1905 is a little shield with a lower case f so does a small shield with lower case m on this case designate 1912? The top of the baseplate is stamped with the Gillette diamond/Known the World Over. Serial number on the outside tube is E154920. Can anyone provide more info on dates or hallmarks?