Thanks to Tom, I've now completed v1.2 - change being it now checks for certain keywords in the category/locale list, rather than for "Great site!"
There's a small chance some spam will be missed, or there will be false positives, I'd appreciate any reports of these.
Of course, I agree totally with Dom's view that we ought to be preventing spam from getting there in the first place, something which I think having real user registration will help with. (We can do things like moderate IP edits, allow certain users to moderate, etc easier.)
Clair