My family come from Ireland, so it is like a second home to me. Like you, I visited Blarney Castle but didn't kiss the Blarney Stone. I guess it was because my little Irish granny from Cork always said I didn't need to kiss the stone as I was full of blarney already. I have never visited Newgrange though. In some ways it is like the Irish Stonehenge and we haven't yet unlocked all its mysteries.You’re descriptions had me visiting those places in my imagination.
The funniest part was that at the age of 11, I said I’d go to England if we also visited Ireland. What? Why? They humored me. The first week we stayed in Dublin and took day trips to Connemara in a jaunting cart, kissed the Blarney Stone, and visited Newgrange. Oh those spiral stones intrigued me. I have always loved Irish, Scottish and English folk ballads. My grandmother would talk about running away to be gypsies. I think she and I may have been that in another life. I am in wonder to this day to have felt, at that age, so drawn to somewhere so far from my daily world.
Here is a webpage for Leeds Castle, which is really one of the most attractive castles in England. Well worth a visit and not far from London.