Hi Darrell, Removing the door quarterlight glass is quite involved, from memory it requires a complete strip down, removing door trim, winding mechanism, and glass before drilling out the two pop rivets hidden in the door rubber channel at the top, this then allows the quarter light assembly which includes one side of the main glass channel, to be angled and removed. It is quite well detailed in the dolomite workshop manual if you have one.
Once you have the assembly out one method is to cut the new rubber where it has a hole for the bottom pivot to avoid removing the no longer available rivet on the top pivot. I had to remove these when I did mine as the bottom end was so rotten. I used chicago nails to replace this rivet. they are available in varying sizes / finishes and are cheap!. They are not nails as the name suggests but are brass leather craft screw rivets. I mounted the female side so it was at the top and looked like the original. I had to shorten the boss to match the depth a couple of mm and then put the male screw in from underneath to hide the screw slot and used thread lock to stop it working loose. Reassembly as they say is a reverse of the process, accompanied by swearing. The two rivets at the top are standard available sizes.
I attach a link to the nails - but there are many to choose from on Ebay.
Good luck
Chris
https://www.ebay.co.uk/itm/Flat-Belt-Sc ... nZ9CWltZ0w