It is quite hard to find a defined list of suppliers of Net- a- Porter. Also they rather mention that they have 'a lot of suppliers around the world' in their Modern Slavery Statement.

Only mention the parts of the world where they have offices and operate: "We have offices and operations in the United States, Europe, Japan, China and Hong Kong, and deliver to more than 180 countries around the world. We have 8 local offices and 7 distribution centres, whichemploy a total of 4,128employees."