What the law says
Sections 32 and 49, Children and Families Act 2014. Code of Practice § 2.1 to 2.6
Local authorities must arrange for children with SEN or disabilities for whom they are responsible, their parents, and young people with SEN or disabilities, to be provided with information and advice about matters relating to their SEN or disabilities, including matters relating to health and social care. This must include information, advice and support on the take up and management of personal budgets.
Local authorities must take steps to make these services known to children, their parents and young people in their area, and to head teachers, principals and proprietors of schools and post 16 institutions.
Information, advice and support services should be impartial, confidential and accessible and should have the capacity to handle face to face, telephone and electronic enquiries.
In plain English
Every local authority in England must have an information, advice and support service, commonly called IASS. This is a free service you can use at any stage of the SEND process.
The key word is impartial. They are there to help you understand the system and your rights, not to represent the LA.
They can attend meetings with you, help you understand documents, and explain what should happen next. The LA should actively publicise this service, not bury it in the local offer.