For my last house, which was a prewired semi, I used B.S.S (Buckley Security Systems) on (087) 2100400. They are based in Blarney, but we were in Carrigaline, so I presume they cover most of Cork.
Very professional job, including, when they found that the builders had cut one of the sensor wires in error, they chased new wires taking care that it was hidden.
No connection, only a satisfied customer.