Possible Clues:

• The North only makes stuff like this
• Many London shops display such material
• Synthetic fabric patented by DuPont
• It's only synthetic next to the North
• Clothes of many Londoners contain this
• Suggestion of route for transatlantic traveller in synthetic material?
• Is the North only a mixture that's synthetic?
• Artificial yarn/fabric
• Stocking items for Tiffany (London)
• Chute fabric