This may be the "Wally" Johnson mentioned in an email from Bill Johnson (dated 30/6/2018):
Wally Johnson, who was Dad (Stephen Johnson) and Maurice’s (Maurice Alan Johnson) first cousin, and a close friend of Dad and Mum, did quite a bit of research into the Johnson (and Bell) family tree. It was all written out on paper, and some time ago I decided to transfer it onto some kind of database designed for such things.
Family Life
Walter married Jacqueline Keller (nee Donald) in 1955 in Chelsea. They may have had a daughter, Rebecca (
https://www.familysearch.org/ark:/61903/1:1:QV7P-5K7G)
Death
Walter died on the 24
th of August 1998 at Bakewell in Derbyshire. His will was proved on the 1
st of February 1999 in London.