As this is just a query if this is correct for your school on Collect when you upload the Census you can annotate the reason for this. If not, you may wish to check your SEN report by going to Reporting > Reports > Support (tab) > SEN.
If no students are listed here but there should be students in the school with a provision you can add this by going to the student profile (search the name in the top right hand search bar) and click onto the support tab. To add the SEN provision click onto the cog next to SEN.