Above is a photo of three Warburton signatures and seals on a 1751 vellum agreement betwixt a consortium of iconic Staffordshire potters who were sourcing Devon ball clay. It was sent to me by Audrey Fussell. The Clay was shipped from Devon to Liverpool, and then, via the River Weaver and packhorse, to Burslem. Other signatories include famous potters such as Thomas Wheildon.
A 1971 book New Hall and its Imitators covers several generations of the family of Warburton potters. Also in October 2016 I posted the story of Warburton Pike who was related to the Devon clay producers.
I notice copies of the book are available on Amazon. I was sent a copy of a few pages of it a while ago. If anyone has more information on the Warburton potters I would be interested to hear it.