Complex sentence: With the exception of Eugene O'Riordan the society decided to establish a Credit Union, thus was the credit union movement started and that was the end for the Dublin central co-operative society and the emergent Investment bank.
Split into simpler sentences: With the exception of Eugene O'Riordan, the society decided to establish a Credit Union. The credit union movement thus started, and that was the end for the Dublin central co-operative society and the emergent investment bank.