Thanks again for the replies. I think I'll keep and eye on him for the next few weeks, and if he remains unhappy I will go back to the school with a view to trying HE at least one day per week. My only reservation with this is that taking him out one day per week could be counter-productive. If he's working on certain things in school he could end up falling behind.
DH's reluctance is the only thing that stops us from HE. To answer PP's question, his view relates to his qualifications - how that would affect him in the long term, etc... and the social side of school. I tried to explain to him that others HE and their children go on to Uni, and he's said that he doesn't give two hoots as he's not willing to take a chance that it'll all work out fine for our LO's. With that point of view there's really not much I can do to shift him.
I think it all goes back to an episode of USA Wife Swap he watched (
) - the one family HE'd their children, and when the swap occurred the other family's Mum sent them to school when it was her turn to enforce her rules on them. Apparently the children performed atrociously in comparison to others of the same age, and I think DH sees that as being how all HE'd children are. Of course, I know that's tripe, but the damage is done to his view of HE now and I can't change that unfortunately.