RootsChat.Com

I think getting the birth certificate is the only way to go, with an accurate DOB you should find him in 1939 or alternately a death record.

Yes, many thanks for your interest.  I'll post any new find.

Find My Past has the 1921 census, it has a free index.

ADDED
Charles isn't Charles Jr. either, since his father is unknown.

Quite so. It helps distinguish the two, even if not entirely accurate, as we now know. Every other man in this family seems to be called Charles!

Interesting. Their daughter, Constance, was born in 1886, so could be a coincidence with the names?

Yes indeed RW, my first cousin, once removed. John was known as Jack in the family. He emigrated to Australia in 1948.
I didn't know he was a baker, like his father and so many in my family, and also didn't have dates for Elizabeth's birth & death, so thanks for that.
May I ask the location of the house you were researching?

The house is in Long Ditton, Surbiton, and I picked up Elizabeth Mary Hanmans (sic) on the 1936 electoral register.  I believe Elizabeth would have been working as a nurse to the elderly man who lived in the house.  His previous nurse had been taken ill and died in December 1936.  He would have been 100 years old at this time.  Although a slightly different spelling, I am convinced this is the same person - as Elizabeth, John Leonard and their son, Philip Reginald, are still in Surbiton (92 Queen's Drive) at the time of the 1939 Register. 

Elizabeth, a trained nurse, joined the Australian Imperial Force (1st Auxiliary Hospital), arriving in Brisbane in 1915 - she returned to England in 1917, and was discharged after contracting pleurisy.  John Leonard Hammans joined the 15th Infantry Battalion on 21 September 1914 in Casino, New South Wales.  Elizabeth must have returned to Australia as she married John in Queensland in 1920.

As you say, Elizabeth and John returned to Australia in 1948, after many years back in England, on board the “Strathaird”, and a photograph of them returning (under the heading “Passengers In Strathaird”) appeared in The Herald (Melbourne, Victoria) of Monday 14 June 1948, page 2.  Hope this link works:

https://trove.nla.gov.au/newspaper/article/247298709?searchTerm=Hammans

Hope this is of interest.  My research obviously was restricted to the actual building and its inhabitants, rather than wider family histories.

PS John's battalion was the 15th, not the 13th as stated in the newspaper.  His military service number was "13", which has perhaps been mixed up.

Are they on the 1871 census as a married couple?  If so - marriage was before census date

Not necessarily; for example (in my own family):

1911 Census
Tom Francis Greenland and Elizabeth Greenland
- married in 1937, after respective first spouses had died.

7 April 1861 Census
Edward Charles Green and Sarah Mary Green (false details)
- married under their real names (Charles Greene and Selina Greene) on 13 May 1861, after Charles's wife "drowned".

31 March 1901 Census
William Allum and Elizabeth Allum
- married on 29 July 1901, this being Elizabeth's fourth bigamous marriage.

1901 Census
Edward Ware and Florence Ware
- never married at all, Edward probably believing he was already legally married to Elizabeth (shown above as Allum).