The Chauny Escape Line is discussed on pp. 148-152 of RAF Evaders, The comprehensive story of thousands of escapers and their escape lines, Western Europe, 1940-1945, by Oliver Clutton-Brock was published by Grub Street, London, in 2009.  It is available from Amazon , Barnes&Noble, and Casemate Publishers.  In addition, according to WorldCat, the world catalogue of library holdings, there are 56 libraries that have copies of the book.  Click here to see their list.