There should be a síneadh fada over the ‘I’ and the ‘I’ should in upper case – as I understand.
If Wikipedia can get it right, one might suppose that Cork City Council could too.
I suppose it is another opportunity to check on my Irish grammar – when ‘h’ is used to change a word, the ‘h’ is lower case. So if the word should start with a capital letter, it is the vowel that is made upper case, not the mutating ‘h’.
So that is why you might see the likes of Hector Ó hEochagain, and Cathal Ó hEochaidh – also surnames such as Ó hÍcí and Ó hÓgain.
To my amount of Irish, it should be Páirc de hÍde - I wonder if Cork City Council will be ordering replacement signs.