As I said in the Time & Tune thread: " I've had some requests from people trying to find particular illustrators of these pamphlets. While my interest is in the music, knowing how Google manages to find things here I thought I would place a list of the illustrators here (over possibly 3 postings as it's a long list).
Given time late I might go through and add them to the individual contents lists."

Year        Term        Illustrator
"Singing Together" with "Rhythm and Melody"
1948        Autumn        Not acknowledged but pictures signed Benison
1949        Spring        Not acknowledged but pictures signed Benison
1949        Autumn        Not acknowledged but pictures signed Benison
1950        Summer        Not acknowledged but pictures signed Benison
1950        Autumn        Not acknowledged but pictures signed Benison
I have now managed to identify the above illustrator as John Benison (1919-1991)
1951        Spring        Not acknowledged but pictures signed Robin Jacques
1951        Summer        Not acknowledged but pictures signed Robin Jacques
1951        Autumn        Not acknowledged but pictures initialled "R.J." (Robin Jacques?)
1952        Spring        Not acknowledged but pictures signed Olga Lehmann
1952        Summer        B. Biro
1952        Autumn        Dennis Bailey
1953        Spring        Monica Walker
1953        Summer        Marjory R. Saynor
1953        Autumn        Judith Brook
1954        Spring        Robin Jacques
1954        Summer        Heather Lacey
1954        Autumn        Felix K. S. Partridge
1955        Spring        Heather Standring
1955        Summer        Faith Jaques
1955        Autumn        Sheila Robinson
1956        Spring        Monica Walker
1956        Summer        Derrick Hass
1956        Autumn        Ian Ribbons
1957        Spring        Barbara Jones
1957        Summer        Derrick Harris
1957        Autumn        Diana Stanley
1958        Spring        Charles Keeping
1958        Summer        Brian Wildsmith
1958        Autumn        Geoffrey Fraser
1959        Spring        Lewis Hart
1959        Summer        Robin Jacques
1959        Autumn        Charles Keeping
1960        Spring        G. W. Adamson
1960        Summer        Graham Oakley
Here the two programmes separate, and have their own booklets.