Sorry no more pics. That's the Roadster seat when I took them out to sort the floors a while ago, so no dismantling required!
You can see the C clips and if you look carefully you can see that the brown diaphragm is held to the frame with silver coloured S clips. If yours is like this, the chances are that you'll find the clips have pulled through the brown diaphragm, so that's the part you may have to replace. Rutters may have the parts in stock, so if you remove the seat it shouldn't take long to sort out.
