You may have missed a year's partial pension in the UK already but don't worry if you have they will probably pay it to you anyway. You need to get your contribution record from the UK (you need to create a mygov.uk account) and apply there. You should apply six months early in Ireland too because there is a long delay for them to get your record from the UK and process everything. Eventually you should get two pensions - the Irish one does take into account your years from the UK via a complex calculation, which may well change in 2021. All a bit of a nightmare - it took me 18 months to sort out my partner's though we got it all eventually - but bottom line, ask for your UK records and check them (4 million people in the UK have some years "missing" for unknown reasons, if you have paper evidence for the missing years you can appeal), and then apply for your UK pension. Once you have some contact back from the UK (ie reference numbers, names), apply for the Irish one. And send everything paper that is requested by registered post, so no-one can claim it didn't arrive. All the letters from the UK go via Gibraltar and take 2-4 weeks to arrive. The Irish contributory pensions section is very overworked but helpful. Get cracking, expect it to take time and effort, but be worth it...