Lots of people have had this problem even though internet should work while roaming in the EU on a Guido membership. Can you post what your APN settings are at the moment?
I doubt that this will work but try changing your APN to 48months.liffeytelecom.com and then toggle airplane mode on and then off again. If that doesn't help then you'll have to contact 48 support and see if they can do anything for you. As I say many people have had this problem but the reason and solution is not clear.
Hi @eoin85 you mean that changing the APN from internet.ch.upcmobile.com to 48months.liffeytelecom.com made it work? If that's the case then perhaps that's the key info that has been missing up to now which would help all others who are having the same problem which would obviously be good news.