Firstly, well done in getting yourself into a <50% LTV position.
If you go to bonkers DOT ie/Money/Compare Mortgages section (Won't let me post the URL), you can see all rates and offers available to you based on a preference of fixed or variable.
I moved from BOI-KBC-AIB a few years back as they each wouldn't match the cheapest rate on the market.
The way I see it is, you have worked hard to get yourself to that position, the minimal admin involved in moving to an alternate bank is negligible to the savings that you would make in the long term of your mortgage.
UB, KBC and AIB are cheapest variable rates out there currently, KBC look to give a larger amount towards Legal Fees but most definitely do not treat their customers as fairly as AIB.
All things being equal, you can see from the website above that going with EBS on 3.3% vs AIB 3.1% variable over the remaining 25 year term would save you €12K and almost €20K respectively based on the rate you pay today.
That small % difference between EBS and AIB can mean a big saving in the bigger picture.
If it were me, I would move to AIB, take their €2k and overpay by the monthly saving you are making.
I imagine BOI would welcome you back with open arms in the future as you are a 'safe bet' with that LTV.
Best of luck.