He is known only from his marriage record.

There are only two registered births that might be his (in England and Wales):

Surname   First name(s)      District   Vol  Page
Births Mar 1902   (>99%)
Law Samuel George Chippenham 5a 65

Surname   First name(s)   Mother   District  Vol  Page
Births Jun 1917   (>99%)
Law Samuel G Raven Shoreditch 1c 65

Then there are two marriages of Samuel G Law; while the first marriage can only be that for the first birth (or an even earlier such birth), the second marriage could be his second oor for the second birth.  My strong suspicion is that his birth was that of 1917.

Then there are three deaths of Samuel G Law between 1920 and c. 1960:

Surname   First name(s)   Age   District   Vol  Page

Deaths Sep 1954   (>99%)
LAW Samuel G 37 Pancras 5d 320
Deaths Mar 1957   (>99%)
LAW Samuel G 55 Ealing 5e 219
LAW Samuel G 74 Epping 5a 39

I just wonder if these are grandfather, son, grandson?

Anyhow that 1954 death is clearly of the 1917 birth, the first 1957 death is clearly that of the 1902 birth.

The three deaths make it likely that the second marriage found for Rosina was as a widow.
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Brenda Graham has found that he was a prisoner of the Japanese and died comparatively young.  Was he the on who died in 1954?
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Their marriage:

Surname   First name(s)   Spouse   District  Vol  Page
Marriages Mar 1946   (>99%)
Cox Julia B Sheehan Finsbury 1b 798
LAW Samuel G O'Connor Finsbury 1b 798
O'Connor Rosina A Law Finsbury 1b 798
Sheehan Thomas S Cox Finsbury 1b 798
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