That's interesting to see your photos, LivingRocks, thanks for that.
I'm not 100% sure how I feel about the whole thing. I mean obviously it was Very Naughty to carve a spiral on a Scheduled Monument, and I don't condone that at all. But once it's there.. well at least it wasn't "Bob woz ere" or (that classic bit of graffiti) a cock 'n' balls. It's quite a nice spiral, it looks like a fern unfolding or something. So smashing it with a rock, it could be said, actually makes it look worse. And is certainly damage to the 'monument' in itself. Whereas if it were left, it'd fill with dirt and lichen and moss and merge into the background a bit. So I do feel that whoever's trying to remove it has kind of got their wires crossed a bit.
ah I don't know. it seems a difficult one to me.