Legal policies and procedures regarding toilet breaks during primary school class time

Currently waiting for a response from WA Department of Education, they should respond promptly and normally no later than (details).

Dear WA Department of Education,
Hope you are well.
Recently my daughter wet herself during class, after her teacher refused her access to the toilet. Apparently the primary school my 3 children attend has banned children from access to the toilet during class time. Can you please send me any legal government policies, procedures or documents regarding children's health, safety and welfare (including mental health) and access to the toilet when they need to go during class time.

With kindness,
Shaun Douglas and family