I have a large 17.5" BLUE WILLOW platter with no marks except an impressed crown, urn, or Prince of Wales three feathers / fleur de lis with ribbons. Upside down it could be a handled urn. I have tried the reference books and Google app for images, also Google images in the browser. It might be a crown because it looks like jewels on top. Thanks in advance. The only crown similar looks like Morley, which might be associated with Mason's or Ashworth.