Murray. Don't despair. I went to a music store that specialized in sheet music and music books. It was just 6 months ago and they ordered the Lester and Seeger book for me. They charged me $12.95 for it.The full title is The Folksinger's Guide to the 12-String Guitar as Played by Leadbelly. It is subtitled An Instruction Manual by Julius Lester and Pete Seeger.
Published by Oak Publications, Order No. OK 61440 ISBN 0.8256.0023.5. Exclusive Distributors: Music Sales Corporation, 225 Park Avenue South, New York NY 10003
or Music Sales Limited, 8/9 Frith Street, London, W1V 5TZ England
or Music Sales Pty. Limited, 120 Rothschild Street, Rosebery, Sydney, NSW 2018, Australia. Good luck!
The book does use guitar tablature to help you get a feel for Lead Belly's technique. I have found it helpful.
Roger in Baltimore