Song at Twilight was originally published in MV Features' Dream A Romantic Picture Story #5. It was reprinted a couple of times in in the UK, in Sabre's Romantic Stories in Pictures #5 and #47.
The first printing in Australia was probably in Page Publications' Romance and Confession Library #79 in 1970 under a Keith Chatto cover:
This story was recycled over the next few years under new Chatto covers:
Love Experiences Library #5
Beautiful Love Stories #4
I'm sure there are more reprintings than these two issues. TBA.