cazpro77Have you found James Prosser b1903 on 1921c? He doesn't appear to be with his family.
Have you looked for Arthur Roberts b1901 on the 1921 census?
For example there is this entry for an Arthur Roberts was he married to Edna
You would need to view the original census for further details
Arthur Roberts 1901 Hackney, LondonEdna Roberts 1902 Tottenham, London
A & E seem to be with Harriet Hancock b1841 Amersham Buckinghamshire
living St Olave, Bermondsey London, Surrey
There was a Harry Freeman living close by, but he seems to be a different person.
So we know even less about Harry than we do about Arthur!
Could he have been the fishmonger? 
It is a very difficult problem.
It certainly is jonWw65
Free index search 1921 census Harry Freeman
occ fishmonger but result shows middle name

Harry
Charles Freeman b1887 Leyton Essex
Others on transcript
Edith Mary b1887 Islington
Maurice Albert b1911 Leyton Essex
living Merton Croydon
1939 London Electoral Register
Henry Charles, Edith Mary, Maurice Albert & Vera Ellen Freeman
Address 20 Crestbrook Avenue
In 1939 Henry's occ
shell fish salesman, he’s with his family as per London Electoral Register
Maurice Freeman Admission Age: 5 Birth 19 Sep 1911
Admission 16 Apr 1917 School: Peckham Rye School
Residence Poor Law Union: Whorlton Road
Father: Henry Freeman