EDIT: this post passed @Sloop John B’s in transit. Basically saying the same thing...
Ireland does use postcodes, but the prefixes cover very large areas, and the last four characters are deliberately not contiguous. The main problem with using them on a public forum is that an Irish postcode corresponds with exactly one address, and you can look that address up very easily.
I would suggest adding a city or county for UK and Ireland to help people decide if they want to collect. Cities are well known, counties are small enough to drive across, and anyone in the country knows where these are in relation to where they live. To anyone outside, it doesn’t matter.
The tag “IRE” is somewhat redundant for international trade reasons, as there’s no difference between sending from Ireland or the EU, whether you’re in Northern Ireland, or the rest of the UK. (Irish and British people get this wrong all the time, but the Common Travel Area between the UK and Ireland allows only for the free movement of people, not goods)