2000 Mitsubishi L200 water coming into back of cab

Not really familar with that car , but on others it is usually caused by bulkhead / scuttle water drains blocked and needing cleared .

I have the same fault. Found water coming in from the ariel. Also behind the rear seats there are 2 vents with seals. The seals are left and right. The near side is ok. But appears they have fitted same seal upside down on the drivers side and it has dried out and cracked. There is not enough room to get the vent out between the cab and the back.