Fiona ,
A few things.
(as per Black Sheep)
1. Your Company pension schemes are separate from your National Insurance contributions, you need to write to/chase up these pension pots.
(there is a uk system and companies that chase for you ,if need be)
2. Your 20 years contributions from National Insurance in UK are ring fenced.Once they hold your current address they will write to you.
(Go onto the UK pensions /tax website and you can get a printout , and request current rules.)
3. Blasted Brexit!
Unless Uk & Europe blow up into war all state contributions are safe , all company pension schemes are safe.
(What we have is uncertainty over values over time , it was always that way but with Brexit we are getting palpitations!)
4. In ROI , @ 45 you also have plenty time to maximize via your ROI contributions to get ROI pension.
What I read from you is that you will get
1. Amalgamation of company pensions.
2. Good part of UK state pension.
3. Most of ROI state pension.
From my reading you are in a good pension place.