Been there, done that. It can be surprisingly difficult, especially in a smaller town, to find a solicitor to assist you in a case against another solicitor.
I understand that the Law Society keeps a list of solicitors who are prepared to act in such cases, but I had a quick look through their website (http://www.lawsociety.ie/) and it does not seem to mention it.
Are you looking for money / compensation or simply matters to be put right ?. Surely if the latter, the best route would be to use the Law Society themselves.
Otherwise, I would suggest using the services of one of the big firms to act for you.
Just go talk to a solicitor about the case. If they are not prepared to take it go to another. Solicitors act against each other all time in these matters. You could also complain to the Law Society, but that is a different route.