When Rob Cowan saw this, http://www.colinscolumn.com/bbc-proms-2022-prom-57-johann-sebastian-bachs-mass-in-b-minor-conducted-by-john-butt-with-age-of-enlightenment-forces-august-29-royal-albert-hall-no-review-but-a-souvenir-photo/, he suggested I consider recordings of the B-minor Mass by Otto Klemperer & Karl Richter.
So, it was Anderson into action. I found Klemperer’s 1967 HMV version easily enough (stellar singers, BBC Chorus, New Philharmonia Orchestra). Richter was a little trickier; he made two recordings, at either end of the 1960s. I assume Rob means the first (as illustrated) and although neither Richter release appears to be on YouTube complete, I found film of a live performance, 1969, that may form the basis of his second issue.
Anyway, I now have the Klemperer and a Richter. Thank-you Rob.