Enquiry about a uninvited guest refusing to leave private residential house and having been forcibly removes?

This happened in the republic of Ireland. My friend hosted a party in the house next door to the house she lives in with her parents- they own both houses, it is private property. At around 6am, after most guest had left, 5 people arrived into the house, uninvited, and refused to leave after being repeatedly asked to. After an hour, 4 of these people overturned a table, and left, but one continued refusing to leave. My friend the host and her mother forcibly dragged the person out of the house, and the gardai arrived after he left. I'd like to know if they were in their rights by forcibly removing him, any other relevant information would be greatly appreciated.