@SJaneS49 fair enough. Didn't want to debate between private vs state. I do think for the non-affluent parents, who are working class or don't work and their DC's are in private schools, I believe shows that those type of parents really care about their DC's education (not saying that parents in state schools don't before I get accused). For the affluent family, it could be just keeping up with the appearances, just throwing money any how, not caring. But I wanted to get across that there's a general consensus that parents place their kids into private schools care about their kids education, even though for some it may be far from the truth.
In the context of SEN. The situation is more complex. I have known some private schools who have excluded children based on their SEN and not want to provide the extra often, often than not, these paying are paying extra to provide 1:1 support/tor therapies at the DC's private schools. There are private special needs schools which often cater to the children with "mild" needs but can following the national curriculum and have in house therapies etc.
Mainstream secondary can be a bit and miss and you have to be extremely lucky and it depends on the profile of your child. At this stage, it's all about pushing results and Ofsted. Most of these mainstream secondaries (and again not all before I get flamed) tend to "leave" the SEN children. They may get some support, or have 1:1 TA's but the strategies are generally not carried across the classes, and some mainstream teachers are just clueless and overstretched with 30 plus kids in a class and Ofsted breathing down their necks. When these happen, SEN children in this predicament, are left through the net and years come later, they have no job, no qualifications, and mental health is through the roof. Not only that, but mainstream schools do not have enough funds for resources let alone kids who have additional needs.
On the flip side, you may get a supportive school (private or state) or your child may end up at a special school and the teachers know what they are doing, they know the strategies, but your child is not getting the differentiated support or the therapies that they need.
It's a tough one. One thing I keep in mind is that your child is just another number, another pupil in their class/school. You really cannot solely rely on a school to help your child. You will have to be the one to "fight" as much for your child to get the appropriate support that he needs... because once your child reaches 16/18- that's it. That's the schools job and then you are left dealing with the aftermath of your child not getting the support for X amount of years. That's why I'm not shocked at all that the SENCo at your child's school said that your child doesn't need it...it's a lot of paperwork for them, they don't need that headache with all the other stuff that they have to get on. So apply for the EHCP for your child, itself.