As well as IPSEA, there are other SEN organisations which may be able to provide you with information and advice.

You will have a local and impartial Information, Advice and Support Service. IAS services are able to help parents review EHC plans, and attend meetings with schools or LAs (depending on service capacity): https://councilfordisabledchildren.org.uk/information-advice-and-support-services-network/find-your-local-ias-service

You may also find the following useful:

Liverpool law school also offers free support with a range of SEN related queries. Support can include detailed letters of advice, SEN appeals support, and pre-action assistance. It may be particularly helpful for parents who are not eligible for legal aid and are seeking support with judicial review.