C & D "Trentham" pattern. Cooper & Dethick (Longton)

I'm posting this because it may help others researching tablewares that are marked 'Trentham C&D' along with the registered design number 252417.
These plates of mine (I have 5) clearly pre-date both Trentham Royal Crown and Trentham Devonshire, but I couldn't find anything regarding an earlier company of that name.
After much searching, I discovered that Trentham is the pattern name, the maker, C&D, is Cooper and Dethick from Longton, a short-lived company operating 1876-1878.