I have a DD with complex SEN, who has always been in special provision. I have seen some of her friends, returned to mainstream, who could not cope and school refused - and were then out of school for a year or more. I met others, who could not cope in mainstream and either had a breakdown or attempted suicide - like an 8 year, who started walking out in front of buses.
Special Needs Jungle reports:
www.specialneedsjungle.com/social-care-tactics-send-problem-parents/
that some LAs take child protection proceedings against parents of children with SEN either because they don't recognise or understand the child's difficulties; or some LA officers don't like parents who disagree with them and stand up for their child.
IMO, inspections of HE would just become another stick for some LAs to beat parents of children with complex SEN, who can't cope in mainstream and end up school refusing. Who apart from educational psychologists, speech therapists and specialist teachers would have the expertise to assess what progress these children were making at home, given their underlying SEN? Its very difficult to get an educational psychologist to assess a child in school for an EHC plan; there certainly aren't enough to assess HE children out of school due to SEN every year.
Furthermore, as this article in Community Care showed in 2015 (and nothing is likely to have got any better since then):
www.communitycare.co.uk/2015/09/02/social-workers-pressured-downgrade-child-protection-cases-referrals-surge/
Social workers were pressured to downgrade children on protection plans to child in need - and leave children suffering neglect where they were, due to lack of resources to put them into care.
I've known two professionals in different professions, who said they made referral after referral to social services about families and social services did nothing, until the family actually were in crisis (like a baby had suffered brain damage)
The more children, who are inspected, the less resources there are for those actually suffering neglect and abuse!