Sorry i didn't get much of the book read to write recommendations MumOfThree, as you know its a bit chaotic here!
Personally, I have an 'avoid confrontation' mindset, so interprete my comments in that light, but I sometimes wonder if it is even possible for these people to get kids like that. I mean if they ahve never seen the light in their eyes when they are learning, or never felt the joy of a new idea, can they possibly understand it?
I don't know really, I guess I'm asking

If I was personally writing a letter like that, I would focus on how much play children can get from learning and how my child needed different learning activities in joyous way in order to enjoy his childhood. (or some heavily revised version of that)
... or I'd chicken out and not send it

As I said, I'm not good at confrontation.