My Dad has an iPhone 4 which was purchased on launch day here in the UK. It was originally mine, but I gave it to him when I got an iPhone 4S. Recently he has not been getting any signal in most places, with only one bar in the odd place or two. We are both on O2, and so is my step-mum and when we compare our signals my Dad tends to have 'No Service', whereas I get 5 Bars with 3G, and so does my step-mum (who has a 3G). I have tried Restoring the phone - but it seems as if there is a problem with the phone itself. I am trying to get my Dad to go to an Apple Store to get it looked at, since it is out of warranty - and they tried to charge him £120 to repair a faulty Home button back in October. Is there anything else I can try? And does anybody know how much Apple will charge to replace it? Thanks so much!