DS2 is 7 and in year 3 at local state m/s.
He has high learning potential (VR 98th, NVT 99.3rd) and HFA with some speech (narrative and pronunciation) delay, sensitivities etc and poor functional, social and non-verbal communication. He lacks any social desire to please and only pays attention for a max of 5 mins at a time on a good day and 30 seconds on a bad day. His attainment at NC is around average.
I am appealing refusal to assess from the LA and in the meantime the senco/head has agreed to use a token reward system to target pre-learning behaviour in class for 10 hours each week. He already has termly visits from SALT and OT and is following 1:1 programmes delivered by the TA.
I have used a token reward system at home with great success. I am hoping that this can be equally successful in enabling access to the curriculum and will unlock achievement - but I am not holding my breath 
. It is not complicated but requires consistency which means that classroom support needs to be on-going rather than the CT or TA getting him back on task and then leaving him (at which point he immediately stops working).
If this could get him sat at a desk, quiet, following instructions and attending (and therefore achieving) I am thinking that grammar or selective indi would be most likely to provide a similar peer group (the autism genes are strong with these ones - to paraphrase Temple Grandin/Darth Vadar).
But what if it doesn't work. He hates following directions at school but is left to his own devices at home and will show an interest in what he has been learning at school. Last week he made a power-point presentation on the Greek Gods - I have never taught him power-point but he experiments, opening new applications and cutting and pasting images from the web.
Please help me think through the alternatives. I have a telephone apt with an educational consultant at potential plus in a couple of weeks but would really appreciate any advice/experience.