Try putting a small amount of cash credit on your account.
€1 is the minimum as far as I recall.
The issue here is the stupid way that Apple do things.
For iPhones/iMessage/FaceTime they need to activate on a new network.
On some networks this requires them to silently and an SMS to a UK activation server.
On some networks (such as 48) international texts are not covered by normal allowances.
On 48 it costs c. 8c to send a UK SMS.
If you don't have cash credit on your account to pay for this then it will fail.
Of course Apple don't make it simple by actually telling you this so most iPhone users end up confused as to why their phones don't work straight off.
So put some cash credit on your account, reboot the phone and wait for this stupid activation process to complete.
If that doesn't work please post back.
Hope this helps.
