We have a lot to be thankful for. it was Richard Bonynge, who was a pianist by training not a professional voice teacher, who discovered the full potential of his wife's voice. That says a lot about the profession of voice teachers.
I recently purchased Mr. Bonynge's book on Chalet Monet and it is full of wonderful photos. I don't believe their son, Adam, has an interest in opera and he'll probably auction off the collection of memorabilia when the time comes.