Usually for one week after transmission from this site.    Scroll down to "Archive Hour" and the Copper/Seeger programme can be heard with a RealPlayer.

As for making the BBC's vast back archive available, this is an ongoing bone of contention. There is the argument often trotted out that in many cases, the BBC acquired rights only for one broadcast and one repeat.   However, I know for certain that this particular programme has gone out at least three times. The issue of rights is a minefield and is, as far as I know, far from being resolved when it comes to online resources.