I don't know if she's familiar to you in Britain but Ireland's Eleanor Shanley is my favourite singer.Get one of her cds,I don't think you'll be disappointed.
I always enjoyed Shirley Collins when I lived in London.
Someone mentioned Judith Durham in a previous thread.She had a crystal clear wonderful voice.Great for the sort of pop The Seekers did but I doubt if Ewan Mac Coll ever have sent her an invitation to The Singers' Club!.Compare Dusty when she was with The Springfields.
I don't think Mary Black has had a mention.Her early stuff was good but she's gone MOR for some time now.