AUDI 80 CABRIOLET WINDOW RATTLE

Today I finally decided to find out why the windows rattle on my 80 Cabriolet. I have removed the door card and had a good look inside. As far as I can see, everything is tight but if I shake the window there's a definite rattle. I noticed when looking from the top of the door with the window down there is a pressure pad which I assume pushes against the glass keeping it cushioned. That said, I can only see a set of pads towards the front of the window and none to the rear. The pads are mounted on white plastic blocks with a half round rubber piece which contacts the glass, these are on either side of the window. My question is, are these an original part and should there be more than one set.I have taken a photo of the part concerend and wonder if anyone has any experience of this, or if they have any part numbers or alternative fixes. I just feel another set further along the frame will help stop the window from moving sideways when travelling over bumps in the road. As always, any help or guidance is greatly appreciated.  Fianlly, if anyone has resolved rattling windows then I would be pleased to hear from you. Rich