There are plenty of existing threads.
Very simply, convert your € to £. Calculate the interest you will earn on the GBP deposit in GBP and then convert the balance (principal plus interest) back to € (use forward or future rates as a guide to the exchange rate you are likely to get-adding on the margin charged by a bank to convert of course).
Then work out what you would get if you left the money on deposit in € here in Ireland (elsewhere).
Finally compare the (future) euro value of your GBP deposit with the future euro value of your euro deposit. If the GBP deposit comes out in front, fair enough, but I would be surprised if the difference is significant, otherwise financial economics are a crock!
Put simply, higher interest rates compensate for weaker exchange rates (among other things). Hence it is very difficult (for Joe Soap) to make money from the strategy described.