The quality of the EHCP will be so much better if there has been a period of assess, plan, do, review. If the child is already known to the EP service and so the EHCP can be based on a knowledge of what approaches do/have worked, and what approaches don’t/haven’t, and why, it’s for the better.
IMO, that may be true of children, who are going to be able to cope with mainstream; but its not true of children, who need to be in special provision. My DD was always in special provision and most of the children I met, it should have been obvious from the moment they opened their mouth or they were asked to relate what the story was about, that they needed to be assessed by an EP and should be in special provision. Assess, plan, do, review is irrelevant to children, where the whole environment of a mainstream classroom is beyond them. Its like going to the doctor with a broken leg, and them saying you need to try intensive physio first!
Pp are talking about auditory processing disorder, which has to be diagnosed by an audiologist, but difficulties with reading could be part of a language disorder, which is diagnosed by a speech and language therapist:
www.asha.org/uploadedFiles/Resource-for-DoJ-10-2014.pdf
My DD had a developmental language disorder, leading to a phonological processing disorder and dyslexia:
www.thecommunicationtrust.org.uk/media/18907/communicating_phonics_phonological_delay.pdf
These were always diagnosed by speech and language therapists.
The LA ed psy assessed DD, aged 4 for her statement and then again in Y2 for phase transfer, when she was aged 6y 8m. She wrote:
"DD appears to be showing some specific learning difficulties in her acquisition of literacy skills, particularly showing difficulties in sequencing of sounds, blending letters, recalling letters, letter/sound confusion and reversals."
The LA ed psy also found DD had significant problems with auditory and working memory, and visual perception.
but the fact you are surprised she is behind is a big indicator that there isn’t anything going on with DD with regards to undiagnosed conditions
I can't count how many parents I have spoken to, who were shell shocked to find that their DC had been diagnosed at 12, 13, 14... with any combination of severe language disorder, dyslexia, dyspraxia, ADHD/ADD or ASD; or MLD bordering on SLD!
OP cannot rely on the school to notice if DC has dyslexia or not. Parents have to be pro-active, if they suspect their children may have SEN - because well behaved girls in particular tend to get overlooked in the classroom, while the children with challenging behaviour get far more input.
My advice to any parent, who suspects dyslexia would be to get first an assessment by an educational psychologist, and then depending on what they say, assessments by a speech and language therapist and OT; because dyslexia can occur with other language deficits or dyspraxia, including visual perception.