One final download link for this discussion.
From about 1971 BBC started also issuing 'Teacher's Notes' for Singing Together. These were not so lavishly illustrated, but made up for it by including more background information on the songs, and often a full piano accompaniment. They also suggested teaching strategies to go with the series. Initially I wasn't actively seeking these, but they do add quite a bit to the collection, so I've grabbed what I can, and (surprise surprise) scanned them in. They all seem to be A4 (giving even more space) and usually match the school term of the pupils' booklets, but sometimes covering a whole school year (three terms).
Singing Together - Teacher's Notes