Did you enable data roaming?
If not try that and power the phone off and on again.
If that doesn't work then try manually scanning for networks.
If you see 48 listed then manually connect to it.
If you don't see 48 listed then connect to O2 instead.
What phone make/model are you using?
If it's an iPhone then additional steps may be needed to activate it - e.g.:
http://community.48months.ie/t5/Need-Help/quot-Your-Cellular-Network-is-restricted-quot/m-p/18329/hi...
Post back with more info and error messages if applicable.
Hope this helps.
