It is always best to check with your local authority whether planning permission is required.
The canopy may fall under Permitted Development guidelines if it is less than 5m from the school boundary and is less than 25% of the total footprint of the building or less than 100 sqm (whichever is less) and has a total height of less than 5m.
If you are planning a very large structure however, planning is likely to be required.
Kensington Systems can provide you with bespoke CGI visualisations to help you apply for planning.
Read more about applying for planning permission for your canopy.