In a recent post (https://en.numista.com/forum/topic50640.html) I mentioned the fact that I would post another countermark. This one will be even more difficult to pin down:
It looks to me like it's a "WW" punch, not a single "W" punched twice, since there seem to be small differences between the two Ws and they are almost perfectly aligned.
I have a hope ─even if only a faint hope─ that some knowledgeable Numista user has seen it some time in the recent or remote past on some other coin...