I had quite forgotten about these two portraits contained in Letters of Eric Gill (1947). They show Gill in completely different lights, one as seen by another artist, the other how Gill liked to portray himself.
The first is a sketch by William Rothenstein (page 83). It isn’t dated but by the look Gill must have been in his 30s. He isn’t wearing glasses and he looks slightly to the right of the spectator, with a determined expression.