Well, it's got a French distribution code (BA924 - Barclay), so that seems to make it at least Europe then! Highly unusual of Decca to use London for Europe, unless they were expecting such low sales that they couldn't justify pressing separate Decca and London editions, so they used London as they couldn't then use Decca in the Americas and Far East. i'm inclined towards "World".
"In 1958 Sir Neville founded the Academy of St Martin in the Fields with a group of friends. It was formed as a conductorless chamber ensemble of top class musicians and in the early years they gathered to rehearse in the front room of Sir Neville's Kensington flat."