although the original question is from a few years back, we have just done this kind of repair ourselves.
In our case the entire blind was missing and peugeot quoted us over £200 to replace it, just for the part. We have just replaced it ourselves or the grand sum of approx £15, plus a little time.
First off, the door panel had to come off, then the channel that the blind rolls down into (bit of persuasion as this is glued in). make sure you keep track of all clips, screws etc.
Take out the small screws at the ends of the black piece that holds the bar. Then slide the bar out. Check which way your blind rolls if there is any of it left on the bar at all.
We bought a cheap pair of car blinds and took the fixings off them. We sewed them together to achieve the correct width for the blind, superglued and double sided taped them to the bar at the bottom (where the original blind was attached) and then fixed a metal pole (from B&Q) to the top by means of sewing a channel to push it through. We then attached two pieces of fabric to the appropriate positions to line up with the fixings in the car at the top of the window, stitching it above and below the pole, and attached two picture hooks to the fabric portions. We then fitted the newly made blind into the holder, reattached the small screws and put everything back together.
The leftover portion of blind and the leftover piece of the metal bar was turned into a wall hanging for the kids bedroom too.
I know it is much easier to just use the kind of blinds you hook and stick on the glass but when you have got used to the fitted ones which can go up whilst the window is open the hook & stick ones just arent good enough!
Cat
May 2012