At my DC's School they will contact the Primary School to get their school report to assess where they are at the moment. They will also make them sit CAT assessments as part on the induction in September then followed by GL assessments. The results of these will determine which set the child will be in. It's not a grammar school but they are very academic. Do all Schools do this and what books/tests do you use to prepare for the assessments? DC is working at greater depth in all subjects and did very well in SATs .