Hi Big Roly,
Andral and Dubois worked for the Musée national des Arts et Traditions Populaires (MnATP), based in Paris, which is now unfortunately closed but about to re-open under a different name (Musée des Civilisations d'Europe et de Méditerranée or MuCEM) in Marseilles in 2013.
They recorded extensively for the museum from 1939 to the early 1980s. Every six months or so, they would go on a "recording trip" in a specific area (for instance the Cantal département in 1959 or the Roussillon in 1963). There, local contacts would introduce them to local singers and musicians and they would go back to Paris with dozens of tapes full of fascinating recordings (made with quality professional equipement). Unfortunately, even though they worked for the French state, they never allowed anybody to listen to the material !
So, for decades, it was virtually unkwown. Then, a few years after Dubois' death (in 1989) and shortly before Andral's passing (in 2004), everything was digitalized.
I was given access to the CDs and could use everything I wanted (which wouldn't have been possible 10 years earlier). I used about 50 of Dubois and Andral's recordings in the "Anthologie", which was a first (only a few extracts had been published by Rounder in the "France" volume of the "Alan Lomax Collection" : Lomax never collected in France and used Andral and Dubois' recordings instead).
Now, although the museum is closed, researchers still have access to the recordings (no real public access, you need a good reason). Everything is still in Paris, in the Bois de Boulogne building where the museum was. The person you should contact is Marie-Barbara Le Gonidec (head of Music at the MucEM). The 1970 recordings in Jersey, Guernsey and Sark ARE fascinating. Jack Le Feuvre sang about 20 songs, maybe more. Brillant stuff.
Hope this helps. Guillaume Veillet