It was Harry Cox, among others, of whom I was thinking. Note, 'he asked me if I knew a song like that and what was my tune?' That is a very telling statement. He understood variants and he understood the setting of tunes to existing texts. Harry's repertoire was very extensive, how? He certainly didn't hide the fact that he was a collector. He was perhaps a little more reticent when it came to the actual creation of songs. But, and here Sean has got it dead right, Harry made up songs, invented verses and variants. The fact is, he was both qualified to do so by immersion in, and I hesitate to use the term, 'the tradition', and he was equipped to do so by a complex knowledge of what 'works' and what does not. And he was not alone in this.