I live in Ireland and it seems that most people I talk to my age and even the older generation, have no idea what benzodiazepaines are. The drug terminology isn't the issue cause I talk about xanax or valium and they still don't know.
I can't speak for the whole of Ireland, but benzo's are most certainly known in Dublin anyway. Go into the city center (especially the quays) and you'll see plenty of people stumbling around on benzo's, heroin and zimmos (zopiclone). Talbot street is nicknamed "tablet street" for a reason. The thing in Ireland is that benzodiazepine's are primarily associated with the junky scene and not really that common in other circles aside from occasionally being used as comedown aids after MDMA and Psychedelic use.