I have a Carminat in my Renault but I haven't used it for navigation in years for the simple reason that Tomtom don't support postal codes in Ireland. Instead I mount my phone on the screen and use Google Maps or Waze to get me to my destination. Both of these apps provide full support for Eircodes, the Irish postal codes. From MyDrive, I can see that Tomtom already has all the data - presumably it would be simple enough to create a waypoints file that could be used from the points of interest menu. That would be an excellent functional workaround even though it would not be as slick as the usual interface.
In reality the message from Tomtom is if you live in Ireland, don't buy a Tomtom device.
In reality the message from Tomtom is if you live in Ireland, don't buy a Tomtom device.