Samsung Galaxy S2 16gb unlocked vgc. Swap for iPhone 4 or 4s+Cash ?

Galaxy S2 in Noble Black. Great condition and a fantastic phone. I now have an iPad so need to go back to iPhone world. For sale 280 or swap for fair condition iPhone 4 or an iPhone 4s with a cash adjustment. Before you pick up the phone, not interested in older iPhones, other Android handsets, Blackberrys or the rusty mini on your driveway. Amicable exchange face-to-face preferred. Battersea/Victoria area. Thanks for looking.