The Duchess of Cambridge made a welcome return to the public stage todaywhen she and Prince William made a visit to the Royal Marsden hospital where they opened a new children’s cancer unit. Kate was wearing a designer who seems to have become a royal favourite, Amanda Wakeley, and looked as elegant as ever in an oatmeal long-sleeved shift dress, described as ‘sculpted felt’. She wore this with her favourite LK Bennett nude court shoes and with her hair soft and flowing.   I know the fashionista press may again have problems with this look, but Kate was spending time with parents and children who were going to be using…