Looks like the original tower is on the left in that picture. The center, and right part built later. According to Wikipedia, the center is a Georgian wing, and the right tower is from the Victorian period. It would be nice to see photos of the inside of the place before they renovated it. I don’t think it’s an historic listed building, so whatever renovations they did, didn’t need prior approval.
Thanks!
https://en.wikipedia.org/wiki/Portlick_Castle
possibly interesting sidebar:
Time Team S20-E09 The Lost Castle of Dundrum - YouTube
https://www.youtube.com/watch?v=m_UrPN13KyM
https://www.youtube.com/watch?v=HU_EmUPokZw