Thank you both, that's great.
I can't pretend to understand UK law's interpretation of Action and Enforcement other than their literal meanings, but I understand that you are saying it's going to be hassle for them and don't poke the bear.
Whether they are calling themselves Hoist, Robinson Way or Lowells, they picked up the debt for peanuts once the six years had elapsed, and even if they get something from one in a dozen, they are in profit.