Look at this positively. At least the school have told you they cannot meet your DS needs. DS went to a nursery who clearly couldn't cater to his needs but as he was quiet, content, so they let him be.
In society, it is better for all children to educated in Mainstream. But for the majority of mainstream schools, they do not have enough funding to support children like ours and the longer Our children a
Even though your philosophy is right in principle, it could be that this philosophy of yours is actually damaging your child. Forget about what you feel and look at your child, his needs, his future.
DS goes to an independent special school at 5, it is further away from home and honestly the school isn't perfect. But the school gave him the foundation skills in order for him to learn. For years, my DS couldn't participate in group activities and couldn't pay attending in class. Now, it's a different story.
DS was non verbal, despite attending Mainstream from 9 months to 5 years of age- you would think being around neurotypical children he would have learnt to. But no, he couldn't as he didn't have the foundation skills in order to learn language/ social skills. Your DS attention difficulties would impact on his ability to learn- it's just that in Mainstream schools, the majority of children do not have difficulties with this and as the curriculum becomes fast paced, your DS is falling behind as he wouldn't have the attention skills to sustain and focus in a fast paced environment.
My DS speech is of a 6 year old and he is 9. He is still severely delayed but he has come along way and that is thanks to the school.
Now, DS school is not great for academics and behaviour. But I knew this already. But since DS now has adequate attention skills and so forth, I am thinking of moving him to a different school which will focus on the things.
Is it a very difficult decision. DS went to a lovely Mainstream school in Reception, the children and the teacher were lovely but my God, he would have fell further and further behind. I do however miss the local aspect of attending a special school but you have to outweigh the good and the bad- for me, improving DS communication skills outweigh my need of him being in a local school (even though it is sad). He actually can talk, communicate with others and has proper friendships because of his improved SLC needs. He doesn't have many friends in his local community, but he has friendships outside of school and I've made an effort for him to join clubs in his Local community.
Anyway, the decision is up to you. There are some independent special schools that cater to high achieving children but who need more support. Don't worry about the distance- it's not an issue. He could get transport and honestly seeing my DS now, all the travelling was worth it.