Been a while since I have posted as I haven't touched the van for over a year thanks to my back surgery.
Went out today to poke some rusty bits and the arch on the rear passenger side drained like a paddling pool when the poker went through it. So I cut it out to investigate.
Looks like there is a bit of a hole in the pillar to the left of the arch. (I will also be sorting that bubbling too)

So a couple of questions:
1. Where the heck can that water have come from? Can it run down from the rear vents into this area? If so is there some sort of drain hole that is clogged.
2. To unpick that panel will I need to remove the sliding door to get at the folded edge?
Cheers in advance
Cyrus