Kensington Palace is a bit like the White House in that half is open to the public and half of the areas are used for junior or less prominent members of the royal family. Princess Margaret lived here previously and William and Kate have an apartment there now. They have a few permanent exhibits on former residents including one on Queen Victoria and Prince Albert. It featured Queen Victoria’s wedding dress which established the tradition of brides wearing white.
Princess Margaret had much more interesting clothes as she had much more freedom in her personal wardrobe. The exhibit used Vogue covers from throughout the decades to help place the clothes in the context of what was trendy.