06-05-2017 04:21 PM - edited 06-05-2017 04:21 PM
There is no add-on for texting UK/international numbers.
Did you buy an EU roaming text add-on?
If so that's no use unless you're traveling to Europe.
You need cash credit on your account to pay for texts to UK numbers (25c per SMS - long texts may use more than one).
Hope this helps.