Hi Pooley, IRMS is correct in terms of digital data however with Admissions paperwork, a lot of schools require parents to fill this out with pen and paper, this manual record must be kept indefinitely in an archive after the main 6 year period has passed after the child has left the school - any digital record can be deleted after the 6th year. (however I personally would check with a DPO before I ever delete any information)
If a child is SEN then yes it is DOB + 25 years (+additional years if review needed), if they are Statemented, DOB + 30 years (+ additional years if review needed), if they are LAC its DOB (from age of 18) + 75 years (IRMS does not quote this on their website for LAC, my LA uses this policy, a number of others do also)
In regards to attendance registers I do stand corrected I was going by an old version of my LA policy that was pre GDPR, requiring manual paper registers to be held for 10 years from register date. I agree with you as above, 1 year for standard, 3 for meals, 6 for FSM - after last date of register.