Harpgirl -
It's an interesting point you raise about the frequency of Tourette's and how it goes unidentified. Since finding there is almost certainly a hereditary link I have recognised all Tom's symptoms in myself, albeit to a much lesser intensity. It comes as something of a surprise to find that in a clinical sense I probably have it myself, and it puts it all in a very different perspective, since it changes nothing. I'm still the same as I was when I thought I was normal (grin), and so is Tom.
Also my brother and sister, both schoolteachers, have taught several kids over the years with Tourette's.

Thank you all for your thoughts, wishes and the effort you have put in on Tom's behalf. I will follow up all the links & recommendations, and report back if anything noteworthy eventuates.