Howard Charles and Kathy (4830)
Masham Pottery
1970s?- Masham, Yorkshire
Via the Masham Gallery website:
"For many years Howard and his wife Kathy ran the Masham Pottery. In this time Howard produced mainly functional domestic ceramics. Now in retirement Howard is concentrating on hand-built figurative work. The pieces are inspired by the paintings of L.S. Lowry and the people he meets in the area."
I've now verified that the CH (or H) and Tree pair of stamps is for Howard Charles, Masham Pottery, based on the sheep decoration on the mug matching the decoration on the set with the Masham label.
Also matched the CH (or HC) monogram stamp to the CH and Tree pair of stamps via the same tree decoration on the stoneware pots.
See 20thCenturyForum for further examples