Interest recent acquisition whilst it's origin is obvious "Royal Mint London" I'm not sure what it's come off.
(http://www.australian-threepence.com/images/seal-1.jpg)
(http://www.australian-threepence.com/images/seal-2.jpg)
Perhaps sealing a crate from the RM containing dies?
Me thinks that came off my last pay packet.......hehehe.
Interesting relic I must say.
Why send the Royal Mint an email and ask them?
It's not very big. Between the size of a threepence and a sixpence.