Goodness, this one looks more suspect than the OP coin? Apart from the general 'look' of it, the pinholes on the reverse 4 o'clock lions and lettering, the poorly formed II of XII. I've only taken a cursory look at the image in Spink, but the OP jewels seem correct, when comparing to that crown cushion?I know you're now going to tell me your coin has provenance going back 200 years, and it's been in the hands of endless collectors...