A digraph is a pair of letters used to write one sound. This is often, but not necessarily, a sound (or more precisely a phoneme) which cannot be expressed using a single letter in the Latin alphabet, for instance the ch and th used in English spelling.
... Potter Gallery[?], Hawkshead[?]
Cumberland Pencil Museum[?], Keswick
Dock Museum[?], Barrow-in-Furness[?]
Kendal Museum[?]
Museum of Lakeland Life[?], ...