I have just been having a good look at my car and rack, got the old man to have a butchers with me inall. We seem to thing the drivers side door has a slight bend in it, so we found some bits of word and bent it back into shape, by the looks of things it has worked.
Also I have done some research since and it seems the doors are easily bent when lent on or when the wind catches them and the door is let go.
Fingers crossed no more leaking