Now here are 3 reasons why accountants get sued. While this comes from a professional indemnity insurance brokerage in the US, the reasons set out have global and Irish applicability.  

In my experience accountant's get sued for investment advice that went wrong.  Not because the advice was poor but rather the risk management steps and documenting the advice was not taken seriously by the accountant, resulting in a knife edge claim where none should exist.

The other basis in my experience is because  fraud was perpetrated by a company on investors and the accountant is sued by the investors because of an apparent failure to unearth the fraud during audit. That's  not the purpose of audit but that's not the point.

That said claims against accountants rarely get heard in open Court.  The reasons being is that the spirit of compromise comes from accountants disdain of a Court trials and the leverage that their knowledge of their client's intimate financial affairs brings.