I believe I have seen this somewhere but I can't recall. Have you recently purchased it? I like the coin, but would not purchase it due to the assayers mark. Which is kind of weird as I love conterstamped and chop marked coins....
I just bought it on ebay. What makes you think its an assayers mark? Seems rather large? I was going to pretend a knights sword struck it in battle.
I have seen that same mark on a few examples and I believe that I read it was an assayers mark on an example in an auction. Though, I could be wrong as I know absolutely nothing about these coins.
Quite a beatiful piece. I love the rampant lion design, so I might be biased to overlook any blemishes.