whacky thought here, but how about if you offered to stay somewhere close by, that way you wouldnt need to find a sitter for your other child, they could come aswell so they were also getting a treat and some quality 1-1 with you, but if need be you were close by if they needed to call on you, with mobile fones these days no-one needs to be out of contact,they are never gonna know if he's upto these trips if never given the chance are they, just a thought, but i think the fact that they have allowed you to build him upto this since before xmas, to then decide they dont think he should go is disgusting, our sn kids miss out on enough as it is. lol at your description of inclusion gess! hope this all works out to everyones advantage hun. xx