Unfortunately lots of people are having problems with UK/EU roaming in the past few months.
And it looks like many never get it working.
If this link doesn't help then you'll probably have to contact 48 support but even then they're unlikely to be able to do anything.
I have had this problem for months.
Every time I go to Belfast I have a problem connecting to the internet.
I have spent hours on the webchat to no avail.
the last person I spoke to said not to use all the settings given in the help section such as MMC and Port etc.
She said just to use the 48months.liffeytelecom.com and leave everything else blank.
I'm so fed up with this we're going to Italy soon and I bet we'll have a problem there too.
Because we're on a cheap plan i think this is deliberate to throw us off it.
I've had the same issue since I went from Ireland to England for a whole month! The support are just blaming "handsets". I'll save you the time and tell you know that I've tried putting my sim in other phones and I even got a replacement sim to try fix the problem and that didn't work so don't bother with that. There's no supoort on this issue despite it being all over the internet now that no one can get these sims to work.