iPhone 4S White 16GB 3 Months Old with proof of purchase on Three (3) Boxed ?

Old had it for 3 months. Fancy the new iPhone 5. Fully boxed. Had screen protectors on since it came out box. All accessories are new and never used. I have proof of purchase. You Will collect it cash on collection from my house. iOS6 available for it next week for free! It is on 3 network. Can be unlocked after bought from the network. Only contact if you are interested. Do not ring on blocked number. Will give new screen protectors with it. £350 no offers or I will keep it! Thanks :)