Problem with Passenger side rear door

[billi2]

I have a 2006 registered 307 hatch and am very happy with the car overall. I live 5 kms down a gravel road so there is a fair amount of dust as we have had long periods of no rain since I purchased the car new.
The passenger side rear door will not open (the car is RH drive). The problem started with the outer handle not working but you could still open the door from the inside albeit it was tight. Last week the inside handle stopped working as well so now I cannot open the door at all. The problem was intermittent and when you opened the door using the inner handle the outer one worked for a while.
Now both inner and outer handles just pull loosely the same as the outer one does when the door is locked.
Can anyone help with any solution to the problem and advise how I get the linings off the door when I can't open the door. I can access the only screw i can find but what do I do then?
I have just found this forum and will be a regular from now on.