Hi, i've had my iphone 4 since first day of launch june 2010 but i think the battery is now starting to fade a little. It's easily always lasted the whole day but now it seems to be getting to like 20% by 6pm at night which it never used to. Since i charge it every night it's possible that it's running out of good life. Anyone know if it's possible to get a replacement battery in an apple store without replacing the whole phone? If so, how much will it cost? (i'm in UK) Cheers!