So were mine. 3/4. My surname is very obviously Irish too. Yet I honestly don't feel even remotely Irish. My mum was raised in Manchester, my dad in North Wales and moved to Manchester at 16. I absolutely 100% consider myself English, and more Welsh actually than Irish, because of my dad and his family living there. I wouldn't blame Grealish for feeling similar re England.
I've always found identity really interesting. Makes me smile when you hear Americans say 'im Irish', with genuine sincerity, when they're referring to someone in their family from about one hundred years ago that they never met, and they couldn't look, act and sound more American. How far do you wanna go back and stop before you decide where you're actually from? Ha. Anyway, sorry to derail the thread. Just think it's a really interesting conversation.