This reading of the song is heavily indebted to the version on Nic Jones’s first album; the tune is his and the repeated zither pattern is a cut-down version of his guitar figure.
If I’ve added anything to it, it’s the sheer quiet of the zither, which I think lends a stillness to the song. The vocal was recorded late at night, close up to the mike, adding to the sense that you’re eavesdropping on a strange and mysterious story. And this is a mysterious song. (Apart from anything else, look at the time she made getting back from the northern shore!)
The text is Child 4E with a couple of modifications, mostly following Nic Jones. In this version she’s a queen‘s daughter; this isn’t an obscure variant, it just came out that way when I sang it and I decided to keep it. Folk process innit.