iPhone 5 , 16G, Black + Slate !

Phone in hand. Unwanted 3 upgrade. Still Sealed in plastic wrapper. Unopened. Phone was supplied by 3, as that is my provider. I was told by carphone warehouse that the phone locks on to the 1st network sim that is inserted, however I have not tested this theory so conduct your own research to confirm this. Looking for cash only - quick sale!!! £470