Any chance it could be part of Manders & Twimble?
http://www.triton.vg/Manders.htmlThey were known for early (contemporary) counterfeits.
I've got quite a few florins, but I've also seen Sixers, shillings & even that 1973 50 cent. I received a bonus One when I brought numerous from a dealer...this coin was bent, so I had a go at bending it back only to take/scrape the plating off.