For £250 a month Revolut would be the way to go. But you must be comfortable using an app on a smartphone.
1) Set up a standing order to pay £250 a month to your personal GBP current account that comes with your Revolut card. So this bit can be automated.
2) Use the Revolut app to manually convert from GBP to EUR. Do this during working hours (Mon-Fri 9-5 etc) and you will get the best exchange rate.
3) Use the Revolut app to create a recurring payment in EUR to your ROI account in Ulster Bank.
4) Relax in the knowledge that you are:
a) getting the best exchange rate
b) aren't paying any fees