Hello,
AIB's reasoning makes no sense to me.
We are talking about a company that will be registered in Ireland, going forward, right?
The volumes that you mention sound more appropriate to Corporate Banking, than Business Banking, but they should have told you that and simply transferred you to another team.
I would expect AIB, Bank of Ireland, Ulster Bank to all be able to provide facilities.
Thereafter, some of the other Banks with Corporate services are also worth speaking to - Barclays, HSBC, BNP, possibly also Citi and Rabobank.
If you don't require credit facilities, and tend to have notable positive balances in your accounts, expect to be hit with an annual fee, in addition to standard fees for transactions etc. Basically, its a cost that Banks are trying to pass on, resulting from the negative interest rate issue.