Just came across this archive of stuff that seems to be like a cross between radio 3 and UBUweb, it looks like a pretty enormous amount of stuff that goes back at least as far as the 70s (i found an interview with Alvin Curran from 1972) and i haven't really looked at it properly (so appologies if it's s waste of time) but I thought it might be of interest to a few people here.
http://radiom.org/
Edit: ignore the spelling of the URL in the title and click the link