There's a hole in my Rangie and it's letting in water!!

With the recent torrential downpours...WTF it's June??....I noticed a small puddle in the footwell, on top of the rubber floor mats I looked around the cabin and found the roof lining was wet, top right hand corner next to the windscreen.
So I've stripped the external trip off...cleanded the gulley along the top of the screen, and applied some silicone sealant....it's still leaking.
Has anyone ever had the roof leak?? (I haven't got a sunroof BTW.)
The roof panel is welded on and the welds covered by the long bits of trim that have the roof bar sliding covers...can those welds crack and allow the roof itself to leak?

How do I remove those bits of trim from the roof??
How do I get the roof lining released enough to see where the waters coming in??

Thanks in advance.

not sure about the roof leak problem
however i have had to have my p38 to auto electrician today as it wont start at all
cut long story short footwell was full of water under the mats drivers side
boll***d some of wiring from Becm to ecu had them replaced codes resync and £170 bobs your uncle
find the leak fast you dont want water in the Becm unit

the guy also told me there was a product recall years ago relating to the plastic trim between the drivers door and the windscreen, was causing leaks.
what they did was remove it cut off the bottom of the three lugs fill the hole with sealant and put it back
maybe an avenue to look at
Carl

Thanks for the help. I don't know if the trim would be to blame in this case, it's getting wet at the top of the A pillar first, then running down..when I removed the trim the water dripped straight from the roof lining onto the floor.
I think I'm going to attack the top of the windscreen with a full tube of sealant and hope for the best!

Fixed the leak!! Sourced it to the roof! I unclipped the roof gutter trim and found alot of debris which i cleaned away.
I found the paint had cracked near the front edge of the roof where the metal is folded and sealed. . On closer inspection there was sealant visible behind the crack in the paint..I dug away at the paint and sealant and blew compressed air into the hole that was left. A small amount of water was blown out of the hole.
So I degreased it a filled the hole and cover the surrounding area with silicon sealant. I repeated this on the other side just in case.
Over the last few days we've had some rain and it's dry as a bone..joy.