Octavia vrs mk2 here!

I think water has got into my fuse box when I lift the lid there was lots of water there at one side , I dried it out and put the lid back on, but when I’m pressing down on the lid it’s making a suction noise and water it dripping out the bottom of the fuse box ☹️ Also my fans have started coming on by themselves every half an hour, could this be due to water 

I'd say it seems fairly likely to be related.  I'd disconnect battery and remove cover and let it dry out for starters. A hairdryer on low/med temp will help speed up process.