The Springfieds had a couple of hits back in the 60s. "Island of Dreams" and "Say I Won't Be There". The tune of the latter being "Au Clair De Lune". In later years, Tom Springfield used the Russian folk tune Stenka Rasin for his composition "The Carnival Is Over" which was a big hit for The Seekers.

Fwiw, I think Dusty was at her best (and by her own admission, happiest) singing Motown and songs of that ilk. That said, she was pure quality no matter what she sang.