Fuse 20 keeps blowing help please

[G5 VWS]

Hi folks

I'm having an issue with the old scirocco.

Fuse number 20 keeps blowing, leading to me having no number plate lights and dash board lights. It just happened all of a sudden with no warning

Recently I have had water getting into the fuse box so I've replaced the fuse box with a new one and fixed the leak. I've also replaced the light switch incase it was causing the problem. I've also replaced the rear number plate lights and holders and bulbs. And finally I've replaced the whole instrument panel for a known working one but the problem is still there.

I'm now at a loss on what to do next. It's really annoying the rest of the electrics are working fine but don't really want to drive the car just incase there are wires shorting out somewhere,

Thanks in advance.

[Little_bro]

Only a long shot but take out the fog light relay as the wire to terminal 4/86 on the relay takes its feed from fuse 20.