Originally Posted by
gMaesterUK Try looking at Settings >> about. Under Phone Information, you'll find Carrier. If it shows it as CV <Country>, for example my phone shows "CV GB", this means it's a SIM free (or country variant) so any SIM card will work, if it shows anything else it's most likely a network-locked phone, the code for the carrier will give it away.
If in doubt, please signup to WindowsCentral and post a reply to this thread stating the Carrier value.
G.
Its a Bush windows phone. The CV identification codes are only applicable to Nokia / Microsoft Lumia phones.
T-Mobile are now merged into the EE network, so you should select EE instead of T-Mobile.