For Android user, after SIM card plug in there will be a notification popping up as image shown below (Image 1). Please choose “Orange UK” option, and then click “OK” to save the setting before you start Internet surfing. Some mobile models would display “EE” or “T-Mobile” option rather than “Orange UK” which are correct alternatives.
For iPhone users, after SIM card plug in the process would be automatic.
The changes would not affect existing users, no further adjustments required.