Whitby possibly couldn't afford Kate Rusby now, or Capercaillie, not that I consider the latter to be folk performers, Folk Rock maybe, but too loud for many people's taste, [on the folk scene that is].
Seth lakeman maybe, but he is on at so many other festivals in the summer. Perhaps as so many of us travel to your town to enjoy the festival as presently constituted, you could return the favour, and travel to any one of many other festivals to see those you nominated?

JM