As to the Leigh FF, the lady you're thinking of may be Kiti Theobald, who is a fine singer (in fact, one of my favourites) of traditional songs, but not what is generally thought of as a traditional or "source" singer.
she is a fine singer who sings traditional songs well,that is all that is important,there are bad traditional singers and goodsingers of traditional songs,give me the latter anytime.
BB,i