I've been getting water in my boot recently too. I've been keeping some big bottles and all of my cleaning stuff in there recently, so it's possible they've just attracted moisture and condensation and that's where it's come from, but when I changed the boot interior light for an LED one a while back, I noticed that the fitting had some corrosion around it, so who knows.
It's pretty reassuring we're all having much the same problems to be honest - although I'm not too happy about the prospect of my clutch pedal snapping anytime soon. Those threads stop me sleeping at night.