The OP's solicitor is guilty of, at worst, bad communication. Many dissatisfied clients are in fact the victims of poor communications, and not necessarily bad legal service. Here's the thing:
1. If you are insured, your insurance company normally gets to deal with your claim and if necessary to nominate the solicitor who handles the claim.
2. The solicitor these days will usually have some correspondence with the insurer, and only if they cannot settle will the insurer let the matter out to their solicitor; so a lot of 'bar room' lawyers will probably tell you that your solicitor should have known from the outset that there was no insurer involved BUT
3. If you run a lot of nightclubs, your insurance is probably on the basis that you pay the first €10 - €30k of each claim yourself. That is the way a lot of nightclubs would operate, so as to keep down their insurance premium.
4. Where a nightclub operator has such insurance arrangements, it would not be unusual for the operator to retain a greater amount of control over claims management - so the involvement of the insurer would not necessarily be apparent (and if there is indeed no insurer, well so be it; though I rather suspect that the club has an insurer but that this case is below whatever threshold operates)
You have paid your solicitor to take the claim through PIAB, (which he\she has presumably done competently?). It appears that you now have what is, in effect, a debt collection case. The money you are owed is probably less than a night's takings (unles you were planning to buy a hell of a lot of furniture), so unless the Defendant is in financial bother I would not have any great worries about not getting paid. the important thing is that the nightclub operator is not rewarded for delay in payment. Once it is made clear that every last cent, and every cent of costs and interest, will be levied, the defendant should see sense.
In short, your solicitor should approach the debt collection like any other debt collection. If your solicitor does not want to do the debt collection work, then you are perfectly free to engage another. You should not expect the original €2k to cover this extra work - and if it does, your solicitor is being very soft on you.
Can I ask what the €2k covered? It seems very light if there were medical reports and perhaps an engineers inspection of the scene of the accident. Or did you pay for these separately? I consider myself cheap (for PIAB work), but my basic minimum fee for any PIAB claim is €1400 plus VAT plus outlay which - even with one medical report - would hit the €2k mark.