Cannot presume that George did marry Mary Sproule. Do you yet have the 1914 birth cert for George giving an exact dob. There are from 1938-40, 2 George Lomax marriages in Bolton.
1938 marries an Emily Starkie. 2 Lomax/Starkie children born, 1939 & 1944
1940 marries an Elsie Monks. She appears in 1939 register but appears to die 1942.
1 Lomax/Monks child born 1942.
The first Lomax/Sproule child born 1943.
John
There's a 1944 baptism in Bolton for a daughter of George Lomax & Emily and to confuse things she has same first name as the 1943 daughter of the Lomax-Sproule marriage. This George's occupation was OHMS (working for government/civil servant)
There was also a George Lomax & Hilda who had 2 sons baptised at Halliwell, Bolton 1945 & 1947. George was in army when elder was baptised in 1945. Elder son had same first name as a son of the George Lomax-Sproule marriage.
Sources:
Lancashire Online Parish Clerks
https://www.lan-opc.org.ukLancashire BMD
There are, I think 4 Lomax birth registrations with mother's maiden surname Sproule in Lancashire BMD indexes, all registered in Bolton district 1943- late 1950s. RootsChat rules don't allow us to give their names as some of them are likely to be alive. You can find them easily on Lancashire BMD by searching for Lomax births with Sproule mother's maiden surname, selecting years 1943-1960 (holding down Control button on my keyboard and selecting those years gives results for the whole run) and choosing "Ignore blank mother's maiden surname".
No Lomax-Sproule marriage on Lancashire BMD or Lancashire Online Parish Clerks.
Any chance Mary Sproule had a previous marriage ?
I'm inclined to think that George and Mary married outside Lancashire and perhaps outside England. Things to find out about Mary which may help. Where was she in September 1939? What else do you know about her apart from her having been born in County Tyrone in 1920? When did she move to England? When did she die? Was there an obituary in a newspaper?
Did George leave a will?