I think I reverted everything back. I don't know the chances of the spammer returning. If it was a bot that scans Google for open wikis then it was probably a one off. The recent changes page should be linked on the sidebar like wikipedia so people who want to fix pages can find it easier.

Update: The same person or bot hit Winamp's wiki too

Update 2: It was definitely a bot. Google is showing 13,000 results using the same phrase "UNDER COSTRUCTION, PLEASE SEE THIS POST IN RESERVE COPY" on multiple wiki sites