Your choice is really limited now to AIB, BoI or permanent tsb.
The default option would be to fix with KBC for three years at 2.3%.
Then when you are ready to trade up, the break fee should be quite low.
And BoI won't be able to bump up your rate when they take over your mortgage.
BoI will be more expensive over three years.
For a mortgage of €100k.
Interest with KBC @2.3% for three years = 6.9%
Interest with BoI @3% for three years = 9% less 2% up front = 7%
+ €1,500 switching costs plus the hassle.
So you are better off staying with KBC.
Brendan