Any ideas on the cause of water under the CD player in an Octy Mk1 Estate?

 

I've sealed around the roof bar bolts, have checked the sunroof drains are free, have sealed around the light cluster and have checked the seam weld around the tailgate.

 

Any other ideas please? :(

Edited 14 August, 20178 yr by reesky

Rear wash tube separated at joiner in the loom by the rear wing/lamp?, it runs inside the wiring loom on the octavia, not the greatest of ideas.

@reesky - As @kentphil1 says, with the note that this is so commonplace a fault that I expected it to be the solution from reading the thread title!