Yes - that approach seems right and will start the ball rolling.
Isn't " And why and by what right is a concerned worldwide public being kept totally in the dark about this precious part
of our shared heritage?" a bit too confrontational for a first communication? Better to work with them if we can.
Once we are up and running and know what we want to do, then a name will follow. In the meantime - how are you going to sign the letter to EH?