"what constitutes English music and, more importantly, what doesn't. You Belong To Me doesn't."

I don't think anyone ever said it did...and it states quite clearly on Kate Rusby's album who wrote it, and it isn't Trad. Arr. Heck if The Bunch (Sandy Denny, Richard and Linda Thompson, Pat Donaldson, Ashley Hutchings, Gerry Conway, Dave Mattacks and Trevor Lucas and Co.)can perform and record some of their favourite rock 'n' roll, and The Ashley Hutchings Big Beat Combo do the same thing ; why can't Kate Rusby record a standard? Though admitedly it was something of a mistake, but that's a personal opinion.