Tim, these are the same as the 60 and 75 of the same period, I'm not sure they are the same as the super 90 (these were the last of the model with uprated engines etc).
a firm in Germany do repair panels, but as you said they are pretty far gone, try ak-autoteile. The only problem is I don't think he will post to uk, or he didn't. I brought some repair panels for a 100 a couple of years back and collected them on a trip. I'll ask my mate in Germany if he has a set that he will part with, if he has I'll be seeing him in October at the Mannheim autojumble so could bring them back.
Otherwise look on German ebay, much more common over there

Stu