The Peter Kennedy Collection was obtained from the Ralph Vaugh Williams Library I understand from this page:
18. The recent [2006?] publication by Rounder of parts of the Alan Lomax Collection and the British Library?s online database make it abundantly (and provably) clear that many recordings he has claimed as his are actually Lomax Foundation or BBC recordings.
25. On the day after his dismissal from his EFDSS post, all his recordings, plus a good deal else, were found to have been stolen from the Sound Library at Cecil Sharp House. Yet they now form part of the Peter Kennedy collection, kept in his house in Gloucester, they feature in the Folktrax catalogue - and likely to be offered for sale now that he has died.
27. Many people have felt unwilling to criticise Kennedy, or to expose his illegal Folktrax publications, on the (pragmatic) grounds that he has actually made the recordings available. They are no longer available from the EFDSS (having been ?stolen?), and much of the BBC material has been lost to technical incompetence and unconcern. Even if this were not the case, BBC licensing charges would put them well outside the reach of most commercial folk record labels. True, the NSA at the British Library has copies - but their copying charges are at professional rates, and their licensing fees for commercial releases are pretty expensive.