The usual approach would be "traditional songs found in Yorkshire"; origins are quite another matter, and nobody who knew what they were talking about has seriously suggested for the best part of a century that any but a very few songs actually "belong" uniquely, or even pre-eminently, to any particular area.

Steve Gardham knows his onions, and if he's to be the arbiter I'd expect the project to be in safe hands in that respect. The word was "traditional", so I wouldn't expect contemporary songwriters based in Yorkshire (whether they are Keith Marsden or Jarvis Cocker) to be included in the first instance.