Thanks to Fr Jim Tucker at 'Dappled Things' who pointed out this excellent BBC Radio program on the history and usage of the prayer: Kyrie eleison. Well worth a listen.
The radio program proper starts after some news and a quick plug for another BBC program, so keep listening. The music on the program is fantastic and begins with the troped Kyrie from the Novus Ordo set to glorious music (in English and Greek) by James Macmillan (just entitled 'Mass') for the Westminster Cathedral Choir, arguably the best church choir in the world! Incidentally James Macmillan is a lay Dominican and often writes excellent contemporary church music for liturgical use. The second choral Kyrie on the recording is from the beautiful Mass for Double Choir by Frank Martin for which the same choir won the choral world's first Gramaphon Record of the Year. The third recording of Palestrina's classic Missa Papae Marcelli is also by this superlative choir whose choral sound is unique and immediately recognizable to an afficionado like myself! There follows a beautiful reflection on Bach's masterpiece Mass in B-minor... and so on.
Do listen: it's a great musical survey/ history of the Kyrie eleison.