I would only test students based on the evidence being presented to me, that clearly demonstrates a significant concern, that is over and above the other students. I would also send out a ’round robin’ to the students other teachers to enquire if they have concerns. I would then meet with the student and discuss with them, look at their work, and depending on the type of feedback or evidence, conduct my assessments.
Do you have a referral process in place? Are staff regularly trained in SEND, and identifying additional needs? Do you have the HOD’s, HOY’s, HMM’s working with you? Do the students sit a test (CAT/SAT, 11+ etc.) before they start at the school? These results are all evidence, and tell a story.
PM me if you want more individual support. It’s a challenging role, and ‘no man is an island’ uh.