Here is an 1839 half sovereign, a coin I rather like. Let me apologize at the lack of photographic skills. See if you can figure out what is unusual about this one:
There are subtle differences as this is not just an off metal strike but rather a pattern. The only other was in the Norweb collection.
Wow! Half sovereign pattern in silver... wouldn't that have been in danger of being confused for a sixpence, perhaps, had it escaped into circulation? I haven't looked up the relative mm sizes.
Yes, exactly and a pattern at that and not an error. The only other one I am aware of was the Norweb example and this was got from Spink a bit over 20 years ago.