Thanks @michaelm . Crunched the numbers. Just short of getting the 500 off the fees for each of them. They all work part-time jobs outside of holiday work. Kind of unfair that students who work (because they have to) are penalised.
@Sharpie. If there are additional people in the household attending full time courses and/or relevant pension contributions are circa 10% or above on the €100,000 euro earnings. That is what it roughly appears to be from my view. I can't get it as my student offspring have part time jobs throughout the year, and I had rental earnings (no more) in 2023. (The government don't account for the fact that the tenants caused more costs than income.)
If you had an change of circumstances ie your income has reduced you can apply to be accessed on the current years income. So if you had rental income in 2023 but have none in 2024 it might be worth your while
If you have PAYE income and you have not maxed your pension contributions allowable for tax relief you could do so to reduce your reckonable income for SUSI. Another option would be cycle-to-work salary sacrifice and just pay it all in one lump.