Are you on a Guido membership? EU roaming only works on Guido. Nothing will work on any other membership when roaming in the EU. Are calls and texts working? If they are then check your internet settings and if the APN field has changed from 48months.liffeytelecom.com then edit it, change it back to that, reboot and see if data starts working. This is a common problem for some people roaming in the EU on a Guido membership and that tip had fixed it for many of them - but not all.
Hope this helps.
I am not a 48 employee so if you need to contact 48 support then use option 3 or the chat facility here.