Newbie - Titanium Tim

Water in A pillars especially LH side, runs down the trim between door pillar and glove box Disco 4 floor mat and carpet naturally soaked. I can hear water sloshing up and down body sill, as it runs down the trim.
HSE 3.0 SDV6 2011.
RH A pillar runs out from Air Bag Cover plate …. Please help, I’m drowning!

Leaking sunroof, maybe.

Welcome to the forum

Hello and welcome

Drill a half-inch hole at the bottom of the A-Pillar and lots of holes on the underside of the sill.
Get ahead of the tin-worm.

As others have said, it's possibly the sunroof drains blocked and the cassette fills with water.
Mine all used to trickle out of the centre light console on my P38 when I braked a bit hard.

Land Rover ownership is a doozie, welcome.

Found the source of your leak yet?