.../...I'm staying away from the SLS parts in this particular instance and I'm buying MB.../...
I can testify to that. My SLS nylon rings have failed totally after only two driving seasons
Mrfatboy, IMHO you are doing only half the job by exchanging the parts in your list.
After fifty years, you may want to also change the bushings (two types) that go each end of the metal linkages, each side of the center gear link (see picture). The "bush front" are installed there, to the right
Part No:s area) 1x A111 268 0797 Lower small rubber boot
b) 2x A111 992 0310 Bush rear, shifter plate
c) 2x A111 992 0410 Bush front, gear box housing