upvc french door warped?

the bottom of my left hand side upvc door which is the opening door does not close tight at the bottom their is a slight gap letting in the draught. I have replaced the seals around the door and also tried adjusting the little rollers but this has made no difference if you are outside you can push the corner of the door in but when you let go it comes back out again my hinges are of a barrell shape but there are 3 places to put allen keys the doors are 10 years old any suggestions as in this weather its cold letting the draught in thanks

keith
February 2010