Hi, we had the instep problem. I wanted some of those doodle shoes for a summer. I went to 2 shops which did not have the size I needed so I went back another day and got told 2 different sizes. I was confused so went to a different town where I found a small shop selling Clarks, Start rite, Elefantine, Ecco and more. I went in and asked for doodles and the manager measured my daughters feet. She told me that te reason no one could decide on a size was because she had a very fat foot with a high instep and doodles would be highly inappropriate. She basically refused to sell me any but did send me home with a lovely pair of sandles that fitted. I always go there now as I trust her to sell me what fits not necessarily what I fancy. A stark truth about buying kids shoes Im afraid. My daughters instep has dropped as they can when they weight bare and we now have a wider choice. Find a shop with a wide range and staff you are comfortable with. They will know what comes uo big,small,narrow,wide etc. They can order bigger sizes for you. You are always best to go to a shop if you can as they are trained to fit properly. Good luck