This website - here - claims this was recorded in 1945.
BEECHAM: Sibelius - Karelia Suite: Alla Marcia & Intermezzo. BBC Sym. [recorded 1945; very few Beecham discs with this orchestra] HMV D.B. 6248. B+ [073235] 12.00
I can't find any clues to the release date, though.