A quick inspection of the detail listing for nearly every camping tent on sale will include the phrase, "no-see-um netting". They know. [Somehow, Daddy Long Legs "spiders" always managed to get inside.]
About mosquitoes in Ireland, if you simply look at the historical regions in which there were natural outbreaks of malaria or yellow fever (Mediterranean basin, South Asia, Southeast Asia, sub-Saharan Africa, coastal east of North America, Central America, Caribbean, and tropical/sub-tropical South America), those locations are natural mosquito habitat--at least for the disease-carrying species.
In 1793, the entire US government (then based in Philadelphia, since the synthetic city of Washington, D.C. had not yet been carved out of unwanted swamp land) had to flee to the hinterland, because of a yellow fever epidemic. Ancient Rome learned to drain the swamps of the capital city. It took the rest of us a couple of thousand years longer to figure it out. (Of course, they thought it was the stinky air released from swamps that caused disease.)
Bob