I'm fairly certain Britain's never issued a "real coin" like that. It sounds like a commemorative medal - they were all the rage in the late 1800's.
There is a catalogue of British medals and medalets, but I don't have one and I can't recall the authour or exact title.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis