That's very interesting and it's been confusing me. I haven't bought any US shoes for this reason. When sellers advertise RL Marlows or Darltons and happen to show the side of the box, the US size is shown as half a size up from the UK size. This may just be for C&J though. I've always thought the 1 size up rule applied till I saw that. Sellers may have a different definition of the phrase 'personal collection'