UPDATE.....We found the family!
Thank you to everyone who took the time to help me with this search.
So what happened? I'm not posting full details for any living person.
I found that James was the 3rd child of 5 of William Devine and Jane Lang. William and Jane were married 3/9/1884 in Hamilton.
1 - Daniel Montgomery Devine b. 30.4.1889 m. 12.2.1918 d. 1.7.1971
2 - Marion Robb Devine b. 5.7.1891 m. 19.3.1926 d. 12.5.1959
3 - James Devine b. 3/8/1893 d. 3/8/1916
4 - Janet Montgomery Devine b. 13/1/1896 went to Canada
5 - Elizabeth Jane Devine b. 12.10.1897 d. 27.12.1965
Daniel Montgomery Devine m Agnes Struthers in 1918. They had one daughter Jane who married in 1945 and she had one son Forbes. Jane died in 1985 and her son died in 2014 but never married or had any children so there was no further way to trace on this line.
All 3 daughters of William and Jane went to Canada at one time, with only Janet settling there and marrying a Mr Dwinford. She came back in 1965 to register the death of her sister Elizabeth. I've tried to trace the family in Canada but not had any response from the emails sent.
Elizabeth came back from Canada and remained in Motherwell for the rest of her life, never marrying.
Marion Robb Devine is the key to how I found living relatives of James. She married Joseph Matthews 19/2/1926 in Motherwell and they lived at 172 Airbles Road. They had 5 children, twin boys who died shortly after their premature birth in 1927 and a daughter and two further sons.
George Matthews b. 24.4.1927 d. 25.4.1927
James Matthews b. 24.4.1927 d. 28.4.1927
Ruth b. 7.6.1928 married Malcolm McKay in 1953 in Motherwell. She died in 2005 and her death was registered by her daughter Marion. I found Marion's marriage in 2009.
William Thomas Matthews b. 29/6/1929 married in 1959 and died in 2008, he had a daughter Dawn, I found her 2nd marriage in 2015.
Joseph Ronald Matthews was born in 1932 and married but I didn't find out anything more.
Through Facebook I was able to find details for both Marion and Dawn - my brother reached out and Marion got in touch and was happy to confirm she was the right person, the great-niece of James Devine! She surprised us totally by informing us that her uncle Joseph Ronald was alive and well and was therefore James' nearest living relative at 87 years old!
My brother runs a Veteran's Support charity at the Kings Church in Motherwell and they are going to get James Devine's medal restored and re-ribboned then framed to be presented back to his family.
We will never know how my step-dad found the medal but we now can put it safely back in the Devine family's hands again.
Thanks for all the help again!
Tracey