...check your windscreen.
I upgraded from a 110 S to an L&K back in January. I wanted lower mileage and a few extras. I knew in advance about potential leaking roof issues but was up for a challenge and the model I bought was absolutely mint condition with only 35k on the clock.
Anyway my arrogance taught me a lesson pretty quickly, not long after buying it, when parked flat or facing downhill water would build in the footwells, it would come under the plastic by the door openings and on to the carpet, classic symptom of a leaking roof (as the drainage runs down the A-pillars). When parking facing up hill the light cluster above the rear view mirror would fill with water, I would then find the cubby under the radio in front of the gear stick full of water after it rained.
I then spent the last few months trying everything. It went to my local garage to be checked, they couldn't find the source of the leak. It went to Skoda, they said the pano roof frame was probably warped (which seems to be something they say a lot) and wanted £1200 to try to repair it which I refused as couldn't afford it. I dropped the roof lining and cleaned the drainage tubes, I followed the popular YouTube guide which involved treating the seals and running small amounts of Captain Tolleys down the frame. I hired a smoke machine to try and find where it was coming from with no luck. No matter what I did, if water got on the roof it ended up coming in. If I washed it or it rained I'd end up with wet carpets that took forever to dry.
I was feeling pretty fed up and then by total chance I noticed something. I was cleaning the inside of the windscreen and noticed that when putting pressure near the top there was flex...surely it couldn't be?
So I spent £180 for a company to come and try and remove and reseal the windscreen, they confirmed straight away that the bonding had gone. Unfortunately upon removal the screen cracked and I had to cough up £450 for a replacement. When it was off (I wish I'd taken photos) I could see right away that this might be the issue. You can actually see straight into the roof lining and into the A-pillars when the screen is removed. They told me that it's a common problem on pano roof Skoda's Audi's and VW's because the glass fitted from the factory has the black surface around the edge embedded in the middle layer of the glass. Whereas on other makes it's on the outside layer. This means that there is no key for the adhesive to grab onto, because there's more flex in the frame of a pano car, the windscreen slowly unseals itself. So the windscreen they put in (which still had the heating elements) was an aftermarket with the black surface on the outside which they keyed before bonding.
I'm pleased to say that my L&K is now totally watertight. I can throw buckets of water on it and I've had it in a jet wash and it's totally dry. What had been happening is that water had been accumulating along the top seal of the windscreen, building up behind and then running straight down the A-pillars. Or if the car was parked facing up hill then it just immediately went into the roof lining and through the light cluster.
Anyway, that's my story and it's worth checking if you're having this issue. A leaking windscreen has the exact same symptoms as a leaking roof, it comes in the exact same places...so definitely check it. Might save you a lot of grief.