Both Bank of Ireland (www.boi.visaoffers.eu) and AIB (www.aib.visoffers.eu) holders can get 15% money back when they use their card to purchase a Just Eat takeaway.
1) Login into the AIB or Bank of Ireland Visa offers page to activate the offer. It's fairly easy to register your debit/credit card there if you've not done so already.
2) Spend at Just Eat with your Visa card.
3) You will get 15% back into your bank account - if your Just Eat costs €30 you would be charged €30 upfront but then get a €4.50 credit back into your bank account.