I believe this was made by 'William Dunningham & Co', but I'm wondering why it does not have a full set of hallmarks. The "W D & Co.", "s" in a diamond, and "925" are all their is. I have two similar cups with only these markings, although the "925" did not strike well on the other cup. Approximately 3" tall.
Am I correct in my attribution? And can someone please help me with a date?