My 2k3 Disco has several of them.

I found the windshield leak right above the rear view mirror. With enough water, I get a trickle down the inside, its obviously coming from a gap in the seal. I can seal it from the bottom, but was wondering if there's any way to get to the top and seal it from there as well.

Everything Ive found online says to pull the finishing strip from the outside, but that's not possible since its fixed around the top of the windshield.

Anyone have any ideas or suggestions?

Also wondering if anyone knows where to find the upper and lower gaskets for the roof rails...

 

It's a common problem on many vehicles. Summer heat and body shell flexure causes the windshield electro bonding to break down and allow capillary water ingress through minute cracks in the resin bonding glue. Usually it never happens after the original windshield has been cracked/broken and replaced but there are no sure guarantees. The cheapest option is to remove the windshield trim and buy some quality marine grade non hardening mastic and run a substantial bead along the joint of the screen and bodywork. Don't do this until the joint has been thoroughly dried out over a few days otherwise you'll be wasting your time. Good luck.

PS. use the same mastic to re-bed the roof rails to the roof.

I'm fortunate, I haven't got any roof rails.