ruggles Actually, I would have thought that TH could help those things (or maybe I've just decided that, in fact, Robin is superman and there's nothing he can't fix!).
Your DS sounds quite similar to mine in that he also isn't good at expressing himself with words, though like harriet's DS, mine is a meltdowner not a basher. Granted he has a speech delay but often in a frustrating situation, I know he has the words to tell me what's wrong etc, but his default position is to meltdown. I also say "use your words" a lot! While TH hasn't sorted this yet, I think it's very slowly improving and he now tries to tell DH what he did each day.
On sleep, I think some kids just need more sleep than others. DS had 2 naps a day until he was over 18 months and still has a nap most days now. I'm not going to encourage him to drop it as he sleeps worse at night when he's overtired.
Harriet my DS also lies awake for a while at bedtime. I'm interested in meditation cds. What cd did you use? I will have a look on amazon. Though you'd better not reply until you're home from holiday! 
As for he sucking collars etc, I second just ignoring people. It isn't harming anyone and i doubt he'll be doing it at university! I've come to the conclusion there are a load of people out there who think that this kind of stuff is a competition and that there is a section on your cv that details when you gave up your dummy, when you were dry at night etc etc! I have visions of adult DC in an interview with interviewer saying "so, you were still sleeping with your mum at 3years old, tut tut..." 
Well, DS still seems a bit off, and yesterday developed a few little blisters round his lips, so now I'm worrying he has hand, foot and mouth. He doesn't have all the symptoms from the nhs website though so not sure. He's been a moody little monster for a few days, mainly because he isn't eating much, I think.