For whatever reason, quietplease.org's "Vale of Glencoe" (97.mp3) file does not download for me. The file (97) doesn't seem to be listed on your mp3 page either:
Speaking of mp3 downloads, RadioLovers.com has a file for a December 1948 "Radio City Playhouse" broadcast of Cooper's play "Three Men" (originally done on "Lights Out!"):
Also, Ernest Chappell is the announcer for a 1945 episode of "Between the Bookends" in which he plugs Westinghouse radio sets with "the new kind of radio" -- FM!: