How i find the previous mobile network of my locked iphone 4? And how i unlock my iphone 4?

My iphone 4 is locked. And i wanna unlock my iphone. I was try with www.iphoneosunlock.com. For unlock i need to know previous network in this iphone 4 and i don't know which mobile network is used in this iphone 4. Then i was search with ( copy trans control center ) and result is ( network country = united kingdom ) and ( network = 07 ) i can't understand this what kind of network is this? I'm searching on internet but can't find the network? Please any body tell me what kind of mobile network is this in UK or tell what i do now?

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1. Hide Pictures and Videos with an ease.
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You can try out you won't regret for sure.