The British Broadcasting Corporation launched recently a new service, Genome Beta. The website
"... contains the BBC listings information which the BBC printed in Radio Times between 1923 and 2009. You can search the site for BBC programmes, people, dates and Radio Times editions."
Type Duke Ellington into the search engine and the list of delicacies thus served is mouth-watering.
The list refers, of course, to programmes broadcast, not recordings archived. How much of this material was subject to the frequent cullings the organisation made to recycle tape or save space is anybody's guess.
I think it is the BBC's intention eventually to make much of its surviving archive available on line as a sort of pay-per-view facility. Perhaps some of these gems will see the light of then and we can watch or listen to the recordings.
Until then, the list makes fascinating reading and is an interesting research tool to develop those Ellingtonian discographies and itineraries. It may be viewed here.