Of which there are only three known from the Caro Collection which Robert Eisenstadt and I bought years ago... when I spotted them on eBay, after first seeing them in a book published 1988.
My example is the piece on the left which is in my bank vault. All three examples are blank obverses.

...and these are the pair seen in Lot 610, Potter & Potter sale #95 and in the above photo.

The value I have on my example is 50% of hammer for the lot; for now...

I am also interested in the oval in the photo.

Please email me any proposals. Thanks.