Although a "small estates procdure", allowing estates of under €25,000 (not €30,000) to be administered without a grant of representation, is mentioned on the Probate Office website, I don't think there's any law to back this up.
As I understand it, this is a reference to the willingness in practice of most financial institutions to release relatively modest amounts of money, in straightforward cases, without insisting on the production of a grant. If their customer has died, and you are the customer's widow/er, the bank reckons you're probably the person who's ultimately entitled to the money in the account, and you're almost certainly the person entitled to take out a grant of representation. So if they pay the money out to you now, the chances that someone else will turn up later with a grant of representation, demanding the money, are pretty low. So they get you to sign a form called an "indemnity" agreeing that if somebody else turns up later with a better claim to the money than you have, you will make sure the bank is not at a loss (i.e. you will pay that person whatever they are entitled to so the bank doesn't have to). You sign the form because you are confident that nobody with a better claim than you will turn up. The bank pays you the money.
Each financial institution decides for itself how much it is willing to pay out in reliance on an indemnity of this kind. The Probate Office website mentions €25,000, presumably on the basis of some knowledge of what position the financial institutions commonly take. But all that matters to you is the position taken by the financial institution that actually has the money in your case. They are not under any obligation to pay out any amount at all, and if they are willing to pay out a modest amount their limit may be either more or less than €25,000.
The bank's attitude will also be coloured by the facts of the case. If you're the deceased's spouse of 40 years, and you produce a will naming your as executor and leaving you the entire estate, the bank will be reasonably comfortable that nobody with a better claim is likely to emerge. But if there is no will and you are the deceased's second cousin once removed and claim to be his nearest relative and entitled to his estate on that basis, the bank will be less confident.
In this case we're not dealing with a bank but with the trustees of a pension scheme/the issuer of a PRSA/the issuer of an ARF, but the same considerations broadly apply. If they are comfortable to pay out a modest amount without a grant, and your claim is less than that amount, great. If that is not the case, there isn't a great deal you can do to change their mind.