For people saying it’s not right to put responsibility to help onto another child. That is correct, however some children, such as those appointed as prefects, or having a nature where they like to please teachers and be made to feel grown up by being asked to do extra things…actually LIKE a task like this.
That doesn’t mean it’s a responsibility to get the other child to class on time. What is means is that for a couple of weeks they act as a buddy system, then report back to a teach on whether it has helped or not. The child feels they have been very grown up, been useful, and enjoyed the praise from the teacher.
It should never be made into a long-term arrangement, however in the short-term it could act as reset for the child who is struggling and build confidence, removing the problem (lateness), and get the child then doing on their own after having some temporary support. Even if that does not happen, the feedback from the other child may give the teacher a better understanding of the problem and the severity of it.
It does seem that the school are being very short-sighted in term of punishing for being late when in this instance it is them leading to school-refusal. It seems it is setting the child into a pattern of a downward spiral. As far a impact on the rest of the class is concerned, I would be asking whether your child is making a lot of noise when entering late and make clear that your child is not expecting a teacher to restart the lesson for them, and that your child is aware that they will just have to jump straight into whatever is happening in class without disrupting anyone else. If you are unable to get the child in due to school refusal or they are late arriving, email the school on every occasion that your child is specially stating the reason for their anxiety over going to school in the morning is the punishments for being late for class, and reiterate (just copy and paste the same email every time), that you believe that if your child could have some leniency such as leaving classes 1min early to have the transition time without the very busy corridors, it would solve all of these issues. Sometimes with schools, you have to just repeat yourself until they give in and
try something. I think given this suggestion has no cost to the school and no impact on other students, it’s not an unreasonable request to try it.
As an aside, has your child ever been in situations such as a football stadium, concert or busy airport lounge? If the child struggles with sensory overload/high anxiety in these situations, that’s an indicator that the issue being experienced at school is part of a wider problem, possibly agoraphobia, social anxiety etc.
If the child isn’t struggling in these types of situations, or even enjoys them…then the issue isn’t about overload and something that is happening at school…could be fears around bullying, could even be that your child doesn’t want to do the schoolwork and is just creating these issues to get their own way and actually wants to be thrown out of class and give you reason why they can’t go into school. The key thing to look for is consistency, if they aren’t always getting overloaded in crowds, then they are trying it on. If your child can’t walk in a corridor with other kids, but can be in a stadium with 5,000 other people…then they certainly don’t have a sensory issue, they have a compliance issue.