Rip of a BBC/Lyrita CD of 1973 and 1980 live premiere peformances of British composer Robert Simpson's Fifth and Sixth 1970's-era symphonies, conducted respectively by Andrew Davis and Charles Groves, and issued in 2021 from the Lyrita archives to commemorate the centerary of Simpson's birth. Both recorded in London's Royal Festival Hall.
The Fifth is a "hard-edged" composition, the Sixth is less so, but both exemplify their twentieth-century roots. Simpson was not satisfied with the performance of the Sixth despite commending the orchestra's skill and the conductor's effort to hold everything together. The problem, the composer acknowledged, was the fact that the orchestra had all of one day to rehearse before the premiere, which he considered inadequate to grasp the "soul" of the piece. Nonetheless, the performance appears spotless to this ear.
Logistics note: I ordered the CD from Amazon around Thanksgiving. It arrived today because it came all the way from...Greece. So if you're tempted, just be aware of that detail.