Hi. I have worked at a speech and language centre in a school with an extremely high (90%+) proportion of EAL pupils. Our speech therapist would often say that if expressive/receptive language and understanding difficulties persist after 2 years from entry into English speaking school, it’s not EAL. A language assessment in the mother tongue might be helpful (do they know their own grammar? Do they understand questions?) but usually lack of progress acquiring the new language is a big red flag re SEND.
I’m not sure how you’d get an EP style report in another language (hard enough in English!) but some of those tests are non-verbal reasoning tests the results of which would be good evidence.