Apparently the woman, a Ms Burns, tried to pull the canvas off the wall. The canvas was protected with Perspex though, and no damage was inflicted. The wonders of acrylic sheeting! The painting is back on display.
Ms Burns is reported to have claimed the painting is bad for children, because it has nudity. It has also been reported that she claims to have a radio in her head. Oh, well, let's not go there! This has raised some interesting debate on the alleged power of nudity, among other things. See Jonathan Jones' blog for an insightful debate along these lines.