The simple answer to this is that it’s the wrong question to be asking. Education has to adapt to meet the needs of the child, not the other way round. A child with Severe Learning Difficulties has the same right to an education matched to their developmental level as a typically developing child.
The more nuanced answer to the question involves thinking about what the school tells you they are expecting of their four year olds in Reception classes and working out what your child can do, what, if anything, they can reasonably be specifically taught to do and what they can’t do for which the school will need to adjust its practices to accommodate your child’s disability. It may be your thinking leads you to the conclusion that your child might have special educational needs and that you need to make a request for an EHC Needs Assessment.
Most of what is talked about as “school readiness” involves self care and the skills for learning as part of a group.
Thinking in broad domains:
Can your child sit? Do they need specialist seating to enable them to do this? Can they sit on the floor? (If not, it’s worth talking about adjustments that the school can make to enable your child to take part in the curriculum together with their peers – it might be usual for whole class teaching to be delivered to children sitting on the floor for Reception children, but it might be better in some cases for all the children to be sitting on chairs rather than the floor or it might be possible to obtain equipment to support your child to sit on the floor rather than for them to remain sitting on a chair whilst the other children sit together on the floor.
Can your child walk? If yes, is walking something they can do enough of, without tiring themselves out, that it’s a reasonable means for them to navigate the school site? If they use a mobility aid, like a stick/crutches/walking frame, what arrangements will the school need to make for them (eg. space to store the mobility aid either by the child’s desk or elsewhere in the classroom, if it’s not needed for short distances).
If your child can walk, but gets fatigued, what are the realistic options? Can they do less walking through the day? Can they have a wheelchair to use when tired? What are the options for playtimes? Although many Reception classes operate with a lot of child led activities, it’s unusual for the children to have the option of being in a space big enough to run around in outside of play times. Most of the children will get a lot out of playtimes where they are allowed to run around so where there are children who will get unduly fatigued by (too much) running around, a solution needs to be created for them that allows them time and space to rest.
If your child can walk but is unsteady on their feet, is it safe enough for them to walk around school generally? If not and they’re using a wheelchair for most travel around the school site, when would it be safe for them to be on their feet and doing some walking?
Is your child independent using a wheelchair – whether manual or self-propelled? If yes, where is there to store/charge the wheelchair when it’s not being used? If not, what adult support is available to supervise them and/or help them move around?
For children who use wheelchairs, what arrangements need to be made to enable them to transfer from their wheelchair to a classroom chair/the floor/a toilet/a changing trolley. If they are very physically dependent and/or have a lot of uncontrolled body movements they are likely to need to be hoisted for their own comfort and for their own safety. Additionally, it is important that nobody is repeatedly lifting a child to provide care, particularly in ways that may pose a risk in the longer term of back problems.
Can your child feed themselves the sort of food they’ll be served at school with the available cutlery? If not, could they do so if supplied with alternative cutlery and/or alternative food?
What are the arrangements for drinks? Can your child serve themselves a cup of water?
If your child doesn’t eat orally, do they know how they are fed? If your child is allergic to a particular food, do they know what they cannot safely eat?
Can your child understand and respond in spoken English? How able is your child to communicate about things that are bothering them to the adults around them? Would they tell someone if they’d hurt themselves? How able are they at communicating with other children? If they’re D/deaf, do they use hearing aids? How much do they know about how their hearing aids work? How much do they need an adult to manage for them? Do they use any form of AAC? Might some AAC help them eg. a communication book – either with symbols/pictures for the child to use to help conveying their meaning or the sort of book where someone who knows the child very well describes their communication.
Is your child fully toilet trained? Do they know how to make sure they’ve cleaned themselves properly? Do they know about needing to wash their hands afterwards? Do they know to tell an adult if they have an accident? Are the facilities in the school suitable in size/location for your child?
If your child has more complex continence needs eg. they need to be cathetrised intermittently and/or they need to wear pull ups because they are incontinent, what do they know about their own needs? Can they change their own pull up? How do the school make sure the children using pull ups aren’t bullied by other children for doing so?
If your child is not yet at a developmental stage where toilet training makes sense, do they know that urine and faeces are waste and not for playing with?
Can your child blow their nose? Do they know used tissues go in a bin? Do their school clothes have pockets for tissues?
Not usually an issue in September, but for the summer of the following year: is your child likely to be able to apply suncream to their arms, legs and face independently?
Can your child put on and take off their own socks and shoes? Can they manage tights, if they wear them? Can they put their own jumper or cardigan on and take it off? What about their coat? Gloves?
If they can’t manage this themselves, do they know what these items of clothing feel like when they’re on properly, so they can get someone to help them?
How much clothing do the Reception children usually change for PE? Can your child manage that?
If your child uses an asthma reliver inhaler / is prescribed an adrenaline auto-injector, what are the arrangements for storing these items safely in the classroom?
How much does your child know about their own medication?
If your child wears glasses some or all of the time, do they know when to wear them and how to store them when not wearing them?
Does your child use any other equipment, eg. splints, a “second skin”? What help do they need to manage it?
Awareness of danger
Would your child know they’re supposed to follow adult instructions?
Does your child know not to take somebody else’s medication?
Sensory processing/other environmental factors
How able is your child to cope with the sensory environment of school? Is it too big/too noisy/otherwise difficult for them? What can be done to make it better for them? Is there somewhere outside the classroom they can go if they are overwhelmed?
For lots of children, including those who are D/deaf, the acoustic performance of the different rooms is important.
Likewise, for lots of children it’s important that the light in the classrooms is good ie. not glaring and with blinds at any windows to avoid their being too much light.