"You won't be surprised to hear that I see support for my views about voice teachers (ie at best a necessary evil, at worst wholly malign) passim"

Where? Not from me!

I've been singing all my life and I really regret not having had singing lessons earlier. Essentially I've been singing badly all my life, even though I was singing well.

Singing lessons have improved my posture, breathing and overall fitness. I've increased my range both up and down.

My sole issue is really an aesthetic one rather than a technical one: she thinks I sound better singing high up; I think I sound better low down. A folk audience might agree with her, for all I know.