iPhone 4S 16GB Black Brand New Sealed Box on Tesco/O2 Network 12 Months Warranty ?

I have got iPhone 4S 16GB in Black Brand New in Sealed Box for sale came as an upgrade from my network provider. This is originally on Tesco network but mostly Tesco phones can be used on O2 as Tesco uses O2 network but I cannot guarantee that its upto you if you want to buy it to use on O2. It comes with full 12 Months warranty from the day you will put your sim card in the handset. This is a genuine sale and I am happy to write a receipt for the proof of purchase and buyer can collect it from my home.