Two thoughts. Perhaps the ON is at the top of the coin, with the N partially cut off. Hard to make a moneyer's name out of what's left, but some moneyers were named with an initial following the Christian name. I'm also wondering if what you're reading as ON looks more like an I with a pellet stop before and after, followed by an N. Also, I'm struck by how the N is not followed by a stop; could we read a mint (or moneyer?) here that starts with NO--- (NORW, NORHT, NORAMPTU)? I believe, occasionally, the mint and moneyer can be rendered without the word ON.
Ok, that's more like three or four thoughts.
And,
