Tailgate Water Leak/Drainage Issue - Rapide S

[robt350c]

Recently after rain, when you lift the tailgate copious amounts of water comes out of the lock mechanism in the tailgate and the carpet on the bottom edge of the tailgate is wet.

Presume either drain holes are blocked or a seal somewhere is leaking (rear central brake light?) or both.

Any ideas?

Can see drain holes at bottom corners of rear glass but not where the water is supposed to exit from the tailgate.

Think this might have happened initially after a jet washing session.

Thanks in advance and Merry Christmas to all!