Yep the rubber that you see around the edge of the door frame.
At first I used Autoglym vinyl and rubber care as I had some in the garage, but then I was in a local motor factors and found this http://www.amazon.co.uk/Holts-RL2R-150ml-Rubber-Lubricant/dp/B00518H8Z6

Was cheaper from the motor factors too!

It's much better and has stopped the creaky noises.

Going to have to try this stuff or something similar. Why would it be the rubber door seals cause when I put the windows down even just a little the creaking goes away??
 
i dont have any creecks in the doors, only had on B pilar wich the clips were broken and Seat changed it, my main issue is the damm roof thats was fixed and the noise went from the top to the left side of the roof drives me insane, need to figure a way of taking it apart and try to fix it since my warranty is gone.
 
My cupra has creeky handles, and it creeks under the speedo inbetween the steering wheel lol
 
Creaking

Just been round my door and tailgate seals with the rubber and nylon lubricant as suggested, and it has sorted my creaking out.Coming off my drive onto the road was getting dreadful creaking,having removed pretty much all of the interior trims it was still there but not now.
 
I've had my car parked for few days now. I bought the Einszett Gummy and I already used it on my car. So hopefully this weekend I'll be able to test if it reduced the creaky doors or if it stills the same.

(The street where I live is full of dirt (mug) so I dont fancy driving my car with this conditions)
 
My cupra has creeky handles, and it creeks under the speedo inbetween the steering wheel lol

I had that creek, turned out it was a slightly misshapen bulkhead mounting point,
thye had to take the whole dash out, hit the bracket with a ammer to striaghten it up, and refit everything.

It's been good as gold since.

Best advise with any creak, is to video it and show that to the tech as you can guarantee, it won't creak when they road test it.