FYI there are several versions of Kit Kat in the UK (and in the US I'm sure). Traditional four-finger bars in traditional silver foil; four-finger bars in 'vending machine' packs (sealed for freshness - yummm...); single-finger 'chunky' bars with thicker chocolate and more crunch; ice-cream bars (which I have never tasted).
Having tasted all but the ice-cream variety, I can testify that the the 'chunky' bars are the best.