I was going to ask how it went on Thursday, Cutted, but I assume your son refused to go?
Here's a bit more 'hindsight advice' from me... 
If I were you, I would not plan to follow the learning schedule the school has planned. Firstly, you're not a teacher (are you?); but more importantly, this is the exactly learning that hasn't been working well for your son. The English national curriculum is fundamentally flawed, imo, because it does not cater for 'experiential learners' - i.e. people who learn by doing rather than sitting still and listening. Since your DS has a possible diagnosis of AHDH, I would pretty much guarantee he is one of these, and that many of his problems at school stem from the fact that most of the learning is simply not designed for the way he learns. As my son (poignantly) put it, when he was in year 9, "I feel like I'm in trouble all the time, just for being me".
Home education and school learning are very different - the latter is significantly shaped by the environment: large numbers of people learning together, the need to find a lesson that will 'work' for all or most of them (though not our own particular kids), and a lack of access to basic things you can learn loads from, like a kitchen or a garden! You have an advantage at home, because it's a much richer environment, and it's specially 'designed' to suit your son.
You can plan learning that uses the things he likes, feel confident with, is interested in, is good at, etc. You can build on his strengths, rather than struggling with his weaknesses. You can - absolutely crucially - make sure he is doing and therefore almost inevitably learning as he goes along... Rather than trying to sit still, read and listen, and therefore (probably) disengaged and struggling.
My other big lesson (one I only learned too late) is that when it comes to keeping kids engaged in education, it doesn't matter what they learn, it matters that they keep their enthusiasm and momentum. My son lost his about 3 years ago, and hasn't yet found them again... He is now really struggling with low self-esteem and low confidence, and has lost important habits and acquired some very negative, unhelpful (and I'd say untrue) beliefs: he has forgotten that learning can be enjoyable, that it can be its own reward; it has been so long since any school/college offered him something he was interested in, that he can barely remember how to be interested; he thinks he is stupid, and believes 'learning is not for me'; he is terrified of going back to college (and is currently refusing) because he recognises he has lost skills - like listening and concentrating and asking the 'right' questions - that he found hard to acquire in the first place; he has developed all sorts of tactics for dealing with being bored, and expects to be bored whenever adults are involved :(
When I look back, I can see that my son has had perhaps a total of 8 weeks (a generous estimate) in the past 4 years where he has been offered something he actually wanted to do... He now really struggles to even conceive that 'something he wants to do' might actually exist... So it's hardly surprising he's feeling alienated and disengaged. I look around and I see lots of other kids (boys especially) in the same situation, and I think as a society we are failing them badly. :(
My instincts tell me that if your DS is curled up on his bed refusing to go to school and feeling miserable, the solution (or possible solution) is to offer him something he wants to do, and something that allows him to do (not sit still, read and listen). School won't give him that. Home ed might, if you break free of the school's 'learning schedule' and create something for him. :)