I posted on the thread in AIBU earlier and thought I'd come over here. 
My DS is 7yo and is in Year 2. He has a diagnosis of Asperger's/HFA. We have wondered for a long time whether he actually has PDA, as he has lots of demand avoidance issues - but he is also very Aspergerish...
In some ways his autism seems very mild - he can interact pretty well with people when he is calm, and he can be very caring and loves cuddles. He is very bright and can be very verbal. However he quickly (and often unpredictably) goes into overload and either zones out or gets very hyper and runs off.
An occupational therapist recently assessed him at school, and thinks he has significant sensory issues - even for a child with ASD. Her report particularly highlighted his movement and sensory seeking behaviour. He is also hypersensitive to noise (unless he's in control of it!). He often spins on the spot (even when he's apparently calm) or bashes into things, or throws things compulsively. He constantly sucks on his fingers or clothes.
He is unable to sit still (he rarely sits at all!) and sometimes he runs out during lessons. He also tends to call out and repeat words as a kind of verbal tic. He is also inappropriately tactile with his classmates, and this has got him into lots of trouble - he is particularly tactile with girls. It is really becoming worrying now as he's about to start Juniors. We are in the process of applying for a statement, which (finally!) everyone agrees is needed.
Anyway... I'm wondering whether to ask for an official diagnosis of SPD, based on the OC's report? I'm not sure if SPD is assumed to be part of ASD, or whether DS's issues would warrant an additional diagnosis.
Also, is there any kind of therapy available for these specific issues? We have not been offered anything at all since the original diagnosis...