This is weird...
I tried the link from Singing Ref, but it gave me only 38 seconds of video clip which then abruptly cut off.
The i-player link Diane mentioned is "no longer available", even though it's not yet 12.59!
The Radio 2 Listen Again has Mike Harding's show, but that again is only extracts.
Where then is this 1 hr 38 minutes?..