Hi,
So, I can narrow it down to these two:
N#108192
N#33219
Apparently, the difference is how many bands there are in the crown. The earlier one has two & the latter has three.
I think yours has three. I'd also note that to the right of the cross in his crown in the outer lettering - the earlier one has a sort of “‡ ” symbol rather than a fleur-de-lis. Yours looks much more like the fleur-de-lis, again pointing to the latter issue.
I don't know how many were ever issued though. I would suspect it was a reasonably common coin - it's not a huge value (4p) and it was apparently minted over 6 years (1504-09). Though how many survived is a totally different question. A quick snoop on ebay suggests coins of that type go for around £300-£400 depending on the quality and turn up infrequently. I would also note there are a few reproductions of the coin.
Not sure if that helps, but might give you somewhere to start.
