Save in ROI or Northern Ireland.

[Northerngirl]

Dont know if this should be in Money Makeover forum. Im earning euro, working in ROI, but living in Northern Ireland. Mortgage is in sterling, which I manually pay in after withdrawing from euro account. Im now looking at saving for a couple of years, say 250euro per month. Should I continue with Aib Regular Saver at 7.10% APR or save in a UK Sterling account at 6.3%. This may be simple to some people, but wondering what would be the better outcome for me?? Thanks.