I know what you mean about tanneries, I used to cut through one on the way to school as a kid, always wondered what all those pits were for and what was in them - now I know no wonder we were chased off.
London furriers had the best dressers, I don’t know if you saw this at http://chestofbooks.com/food/household/Woman-Encyclopaedia-1...
, another interesting article. Until I read the “Popular Mechanics” magazine article I hadn’t realised seal skins were shipped “wet” in barrels.
In the search I did there was also a newspaper article about a US Court case where 2 brothers, both former London dressers, had invented a machine to remove the course hair from the seal pelts. They were suing someone for Patent copying.