I don't think that there is any centralised credit rating agency in Ireland.
I know - they seem to have started that in recent years. Previously I seem to recall that they drew a clear distinction between the terms "history" and "rating". What they provide is definitely the latter which is merely input data for determining the latter (something which is somewhat subjective). ICB really should use clearer and less ambiguous terminology. Note what CitizensInformation says on this issue:ICB actually use the terms 'Credit Rating' and 'Your Credit Rating' on the site, they seem to see it as being interchangable with 'Credit History'.
Credit Rating
The ICB does not score citizens on the basis of their credit history. It simply records information and passes this information to lenders who make their own credit assessment based on the details available on the files.