Google Scholar yielded a few sample dissertations with content on music teaching as well as a text title, English Ways: Conversations with English Choral Conductors, Sanborg J. & Rutter J. 2001, Hunshaw Music Inc. Sadly, I have yet to find this in a library catalogue so plan to request it through inter loan if possible.
Other Directors/Conductors of note which came up in my search were: John Eliot Gardiner; Simon Halrey and Stephen Cleobury.