Whilst I use a 5S as my daily driver, I develop apps and so test them with my old iPhone 4. This phone is terrible though whilst yes its slow, the yellow marks on the screen and the fact that NONE of the buttons work properly (I have to plug it or text it to wake the screen) make me think I should probably get a replacement. However whilst it is well an truly out of warranty, is it not true that under the 6 year consumer goods law the device doesn't function as advertised and I should be looking at a free replacement? The phone has never been dropped marked or scuffed and it works fine, apart from the fact the hardware is just in a terrible condition. What do you think? Would a replacement be warranted under UK law?