I think it does depend on what data you want. It really is a challenge though to find easy to analyse data. Even within school the range of key stages, subjects etc and the various national measures – you have to be clear what you want. I would also be interested in any useful links. Here are the ones I know of: https://www.gov.uk/government/collections/statistics-special-educational-needs-sen
https://schoolleaders.thekeysupport.com/pupils-and-parents/sen/managing/national-data-sen/ (if you have access to The Key)
https://www.specialneedsjungle.com/send-stats-2022-how-pandemic-affected-numbers-pupils/