Quite apart from anything else, Norma is a singer from a traditional as well as revival background, and she sings in the old style; there is stylistic influence from her Irish-born maternal grandmother as well as from traditional English -particularly Yorkshire- idioms.  June is a "trained" revival singer with, so far as I know, no traditional background, which might account for her sometimes rather exaggerated stylistic quirks and very un-traditional, histrionic delivery.  It's powerful and impressive, of course, and she can hold a note longer and more accurately than Norma can, but Norma's approach is the real thing, where June's is in a sense an imaginative and over-romanticised reconstruction; highly-polished and often beautiful, but, in the end, Art music rather than Folk music.  For that reason if for no other, to compare the two as if they were actually doing the same thing is a bit of a dead end from the point of view of analysis.

Malcolm