Royal Canin Diabetic food shipping to Ireland

Does anyone know where you can buy Royal Canin cheaper online and ship to Ireland.

I run a shelter and have 3 cats with Diabetes recently diagnosed and want to switch their food to Diabetic royal canin

I've tried various foods and it's all the guys will eat, they've been spoiled it's my fault.

Thanks in advance, we're dealing with the vets for treatment but they can't advise where to buy it.