I have been inspecting the door mechanism and think I have found the answer,but question is can i do the adjustment.I hope you can see photo on here
http://tinypic.com/view.php?pic=dcsj8i&s=5
Comparing the cone with the other side I can see that when the door is closed the good side still has one full turn of wire on the cone but the one in the picture is fully expanded.It is attached to the narrow rod which attaches to a larger rod upon which the main tension spring is fitted.
Question...If I loosen the grub screws which tighten the narrow rod to the larger one can I then turn it to take up the slack on the wire.
Hope this makes sense.