It might be worth trying to track down the number for the main Seat customer services and push the issue with them. Perhaps go in and ask your local dealer for it, it might make them realise you're serious.
Right here goes:
Just had the car up on the ramps at work, and Im quite scared/pi$$ed off.
The brake pads on 3 of the brakes have shifted, ie on the sides that I can see the pads have moved at least 2 cm down the disc and are pointing out the bottom (you cant actually see the pads when looking from the top).
Are the pads not held in place by anything, like they are on other cars? ie a silver clip? I cant see anything like that on mine.
I guess the drop in fluid is due to the fact that the brakes have shifted so much!
This is not right is it? I need a bit of advice before I phone tha lady up and completely go mad, 3000 miles with your son in the back worries me slightly!!