A couple of these came to light. One outside the house, the other inside.
Pale Brindled Beauty - Phigalia pilosaria.
Both were males: the females are wingless.
This broad-leaf species is regarded as scarce in NW Ireland, but is probably just under-recorded.
Not quite the beauty that its name would suggest....I rather think the people who gave the names out were having a bit of a giggle to themselves.
This is a species that has two forms: one dark, the other pale. The dark version flourished in polluted places like central London, where it still outnumbers the pale version by 60:40. Ours are pale, of course.