Bongo Fury

Recently after purchase (96 2.5D 2WD) I've noticed wet patches on the headlining by the a pillar on the passengers side and a bit on the driver's side. After looking a bit further, this looks to be from around the windscreen area. Ive had a look behind the headliner on the passengers side and this certainly looks to be the area is coming in, water on the windscreen surround.
Looking at the windscreen it looks to be bonded in so I was wondering how this could be solved. I don't fancy having to get the windscreen replaced. I know I has been done in the past so could be a leak from that?
Would it be possible to use some silicone (PU) applied from inside to try and stop the leak? Or would you recommend from outside around the rubber?

Just a thought, but most windscreen replacements come with a lifetime warranty with regards to leaks, might be worth exploring this avenue.

That was my thought but it was the previous owner and he doesn't remember who did it sadly.
I've got someone coming out tomorrow to have a look regarding taking it out and bonding it back in

Always seal the leak from the outside, if you stop it from the inside all you may do is redirect the leak to come in somewhere else