My kids are attending school in DBS and last year my elder daughter was in Reception, in her class there were around 27-28 children, and when we complained they said we compensated this increase by adding one more assitant to the class. So one Teacher and 2 assistants, but it was clear that one more assistant can not replace the main teacher's full attention!
This year the average number is getting less 20-23, but this time compensated by smaller classes..