Thanks, Malone and AlwaysPuzzled.
That's embarassing! Funny how the brain plays tricks. Just when I was writing my post, I was recalling that while the puzzle was referring to Poulenc and his mates, Borodin and his pals could have been included thematically at a push, if they hadn't already been covered by (4,4) the Dave Brubeck title. Also the erroneous nationality I ascribed has been on my mind a lot recently.
To compound my shame, I'm still struggling with the area of my original enquiry. I thought I should be able to fit "EIGHT" into the entry, but I have got ?IR?O?C?ON?. Thinking transatlantically hasn't helped, I'm afraid