Apologies if anyone's already drawn attention to this but I had a quick search and haven't seen any recent posts on it.
Bank of Ireland's SSIA follow up had been paying ECB on any lump sum [Matured Blanace] retained in the Bonus Saver Account after the SSIA matured, and ECB + 2.75% (6.75%) on any new savings after that date [Regular Savings Balance].
They've now withdrawn this, and the rate on all monies in those accounts is down to 3.75%. It's also expressed as a variable rate (not ECB linked) and at the discretion of the bank.
The letter I got from BoI yesterday said "Now that your account is approaching its 18th month anniversary [...]", so they may be tailoring the rate withdrawal to individual saver's SSIA maturities... but if you've been saving there, it may be time to examine other options.