I've always wanted to know this. This subject was discussed on this forum thread:
http://forums.stevehoffman.tv/thread....186121/page-2
and Vaughan-Williams as a suggestion for the classical interpolation sounds very plausible to me. He wrote nine symphonies- when I have a free weekend I might listen to them all to see if I can identify it (or maybe not!).
I can remember listening to the orchestra come in on
Searching for Madge for the first time about 26 years ago, thinking, "crikey, what's going on here, I'm going to have to take this cassette back to Woolworths, there's some sort of fault on the tape!".
edit:
This post suggests it's Vaughan Williams'
London Symphony
http://ledge.fleetwoodmac.net/showthread.php?t=41570