“The Children Act 1989, s 17 and the general duty on local authorities to safeguard and promote the welfare of children within their area who are in need (including children with mental and physical disabilities) has been a powerful tool in the children’s rights armoury. But it’s limitations have been shown by cases like R v Bexley London Borough Council, Ex Parte B 3 CCLR March 2000 (decided on 31st July 1995)” Critically assess this observation.