Mine leaks in that corner, when you cant see the water, its running down the inside of the A pillar and into the sill.
If you peel back the carpet, there's a gromet on the inner sill near the front seat mounting hole. remove that and look inside the sill. you'll see if it's wet.
2 possibilities here
The windscreen BOND has failed - that seal on the screen isn't a seal, it's trim and it doesn't keep water out.
the chassis flex over the years has cracked the sealer on the roof skin underneath the roof trims. you'll see if the paint has cracked.
p.s you might need to take the front seat out to get the carpet back far enough.