Today I was walking around the town and saw 2 Gardaí telling a homeless guy outside a shop to move on. I had my camera with me and proceeded to take a few shots. As I was walking off, one of the Gards came up to me and told me I wasn't allowed to take photos of them. I informed him that it was a public space and I could take any photos I wanted. He then said to me that he didn't give me permission to take his photo. I told him I didn't need any permission from him. He then just says "Fair enough", and walked off.
A few minutes later they drove very slowly past me and glared at me. A few mins later down another side street they drove slowly by and stared at me. I felt very intimidated by the whole experience.
I assume I'm correct in what I informed him about my rights to take photos in public?