Ideally you would be able to test the symptomatic members of your household. Please share these results with the school and if negative your child can be admitted into school the next day.
If your child has Covid symptoms and you can’t obtain a test due to the current shortage, your child must remain in self isolation for 10 days from the onset of the symptoms.
If your child does not have symptoms but a member of the household does, they will need to isolate for 14 days unless a negative test result for the symptomatic person can be provided to the school.
An explanation of the new 3 tier system can be found here.
PHE have produced a letter to parents which explains when a person requires a coronavirus test and what the symptoms of coronavirus are. You can read it here
General Government advise on testing can be found here
Details of the Covid-19 App can be found here
There is now a new legal duty to self-isolate, you can find out details here