As I didn't know the lovely lady very well, I can only really comment on my experience of her on professional engagements in which we both took part. As a "new girl" on the concert platform all these years ago, I was somewhat in awe of her, partly because of her wonderful, beautiful voice, and partly because of her vast musical experience and reputation. Sharing a dressing-room with her during our oratorio appearances in Falkirk was always an illuminating experience for me, as morsels of professional advice would drop from her mouth and be hungrily devoured by me, and eventually passed on to my own singing students. "Never turn up for a concert with only one frock; anything could happen to it (zip bursting, colour clashing with that of the other soloist's frock, DESPITE having liaised with said wifie!!,  coffee spilling, and so on). Stand before the orchestral intro. to your aria, and remain standing until they finish playing, despite any other instructions! Take your own mirror with you; there won't always be one provided!"
Helen had some slightly irreverent, but never unkind, reminiscences of sopranos with whom she had sung, usually followed, as we were laughing, by "You didn't hear that from me!!" She was always generous with performance tips and suggestions for repertoire. She would gently proffer criticism, but in such a way that it was heard as friendly advice for improving one's future performance, for which I was most grateful.
R.I.P., dear Helen; a huge loss to the musical world and to all your friends and family.