4G Setting Gone?

[ShinOrochiX]

I was checking out the SP and saw the 4G/WCDMA/GSM setting under mobile data but when I entered my SIM (3UK-which have rolled out 4G for existing customers) settings are downloaded and the 4G option is gone-I am stuck with WCDMA and GSM. Why? 

Also I am on the latest firmware for my region, 4.1.2.

[_alexdon_]

http://talk.sonymobile.com/t5/Xperia-SP/Cannot-enable-LTE-on-Xperia-SP-C5303/td-p/586089

Check out this topic.