@davidclarke-You might reach out to Kent McCollum at Electrostatic Solutions in the midwest. I know he restores the original Quad and the ’63. He restored my originals that I purchased in 1973, added a protection circuit, and more modern, standard connectors for power and signal input. They sound great!
You have certainly covered some ground in terms of great historical speakers. The first high end dealer I knew of as a youngster in Pittsburgh, Opus One, had used double KLH 9s back in the day.
As to claims and redress, you’ll have to explore your options. Sometimes state laws aimed at consumer protection allow for recovery of treble damages and attorney’s fees. Easy enough to look at the state law in question and do a search of relevant consumer protection laws. You’ll likely have to hire a lawyer in that jurisdiction (unless you want to sue them in your home state and risk that they won’t appear).
It will come down to a cost/benefit analysis for you-- unless you are simply vindicating principle, which is noble, but a rich man’s game. (I was a NYC lawyer for 36 years, now retired, who specialized in copyright matters; no legal advice intended here). Good luck.