Special Educational Needs = a child who has difficulty in accessing the curriculum. The reason might be medical, developmental or social. A child who is deaf would be considered to have SEN and appropriate adaptations might be needed for him.
Equally a child from a chaotic and neglectful home where he gets inadequate sleep might also have difficulty accessing the curriculum..he has SEN but no actual SN.
SN = my child is deemed to have special needs because he has a diagnosis of autism, mild learning difficulties and ADHD as well as dyspraxia...this means he struggles with day to day things like crossing the road. He also has SEN because he needs support to help him cope with classroom noises.
The child from the neglectful home does not have SN, he can cross a road, he can wash and dress himself....but the fact he is tired means he needs support in the classroom.
Over the past 15 years teachers have seen a rise in the numbers of children starting school and lacking some basic skills that in the past they would have had. They are noting a lack in social skills which needs to be tackled before they can even begin the process of teaching these children.
There are any number of reasons for that....children having too much access to computer equipment, phones or parents who do and never bother interacting. THAT is what OFSTED are seeing and rightly raising....lots of children who should not be struggling to access he curriculum ARE struggling. But the teachers are not diagnosing anything...simply identifying children who are struggling.....some struggle because of undiagnosed development issues such as autism or ADHD. Others struggle because of their circumstances.....home, divorce, drug using parents or other circumstances.
These children are then identified as having a SEN and a plan is put together to help them achieve. Some will cope wit the intervention and no longer require it after a while, some will continue to struggle until they are eventually diagnosed with some form of developmental issue, some will continue to struggle either because there is something in the child's background which is impacting upon the learning or because they continue to have an undiagnosed SN.