Walmisley was an alum of both St. John’s and Jesus Colleges and a professor of music at Trinity College, Cambridge. Almost all of his surviving works are Anglican anthems and chants, and a couple of organ pieces.
The anthem sets just one verse of Psalm 115, and then has "hallelujah" for the second half of the piece, so obviously it wasn't intended for use in Lent! Perhaps it was an introit at some point. It has a few extra notes for the altos in the slow section (probably to be split across the aisle) but otherwise is in a very straightforward four part texture with the organ in a supporting role.