Thank you, Freddy. The two Attenborough programmes are far more useful than all my clips!
I think the Margaret Barry concert was at the Bedford Arms, which we used to visit when my son lived in Balham.

There are two editions of David Attenborough on Desert Island Discs. Just search for them on Google;

Saturday 10 March 1979 https://www.bbc.co.uk/programmes/p009mxny
Roy Plomley's castaway is zoologist David Attenborough.

Sunday 29 January 2012 https://www.bbc.co.uk/programmes/b01b8yy0
For the 70th anniversary edition of Desert Island Discs, Sir David Attenborough chooses his eight tracks, book and luxury item for the desert island. Presented by Kirsty Young.