Maryz, if we had a flat roof that would be great. Unfortunately, DS's bedroom does have a roof window that he could climb out of if he wanted to, but it leads onto a very sloping roof that is 4 storeys high
. Even the man who came to fix the TV arial refused to climb up on our roof! Now I'm panicking about him climbing out of the window!
The door is made of UPVC, but I don't understand about the dummy handles, squidworth. Do you mean that you can only turn the handle if the key is in the lock? That sounds like a good idea. I need to get a locksmith in to advise me, and then get some costings for various solutions. We are waiting to hear from OT, the doctor made the referral about 3 weeks ago. I'll ask them then.
We're lucky in that we got a Dx young, when he was 5. We're on our third school, though- he used to run away from the others, but he tends to stay at this one. I'd better get in touch with them and warn them
. Luckily, the school he attends now is well set up for him, he has several places to run to, and is able to use a space hopper round the corridors, and other ways to get it out of his system. The problem at home is that when it's me he's upset with, he can't escape the strength of his feelings, so running away from me seems the only way. It doesn't happen often, thankfully, but when it does, he just wants to get away from me 
Corny, it's intersting that your ds's teacher says about them regulating themselves. It fits in very well with what I've been reading recently in The Whole Brain Child. I really need to finish this book!
You're all so kind and lovely and helpful. Thanks! On a good note, we had another day together today (DS's school having training days until tomorrow), and we had a much happier day 