Have to disagree with Petula Clark being the squarest. I think she had to shake off being a child star in this country, which meant going to France and being a big recording act there, whilst she fell out of favour with the idiotic Brits.
Dusty was the artist - of both sexes - whose voice still sounds contemporary today, and you can hear her on many TV adverts for Carling and Cadbury, etc.
She died far too early...