1. You're thinking of buying two rental properties in Newry. I know nothing of the potential rental income in Newry, but a trawl through rental websites there should give you enough information re rental opportunities.
2. I know something of the rental opportunities/non-opportunities in Spain. Contrary to popular belief, it isn't a guarantee to good (or any) rental income. In Spain, there is 24% take on short term rentals by the local council. If you use a rental agency you're looking at another 20% for the agent. You're asking how you can make a few bob there? No matter what anybody tells you it ain't easy but it can be done, but you will have to live there and do the rent-outs, cleaning, meet-and-greet etc. The upside is for what you would pay for two properties in Newry you'd get more properties in Spain. Since we retired five years ago we spend the equivalent of six months in Spain each year. (I know what I'm talking about).