Here's a summary so far:
GRM timeline
Birthplace: possibly London (Highbury/Arsenal) per 2nd family tradition; Newark per prison records.
Mother: possibly French. Father: horse breeder. Siblings: Frederick, Rosemary - all per 2nd family tradition; GRM claimed they all died in WW2, and that his birth records had been destroyed in a fire.
1899-1900: Birthdate, per 2nd marriage cert.
1900 (9 Dec): Birthdate, per death registration.
1904-1905: Birthdate, per 1st marriage cert
1934 (3 Feb): Gordon Roland MARKERSON (bach, 29, engineer) marries Phyllis Emily OAKLEY (17), Aylesbury reg office. His father George, a colt breaker (decd). Bride & groom both of Swan House, Cuddington. Witnesses likely related to Phyllis.
1934 (Sep qtr): Son born, first marriage.
1938 (Mar qtr): Daughter born, first marriage (now decd).
1940 (Jun qtr): Daughter born, first marriage.
1944-5 (abt): Left his family and went to join the Army (per first family). Served in Green Howards, Claypit Lane, Leeds (per second family, who have a portrait of him in the Green Howards).
1945 (April): Son born, first marriage (now decd).
1945 (10 Sep): Gordon Richard MARKINSON (bach, 45, tram car cleaner) marries Nora REDDINGTON (40), Leeds. His father George, decd (no occupation stated). Marriage witnessed by friends Margaret McPherson & Daniel Hopkins (now deceased).
1947 (Sep qtr): Son born, second marriage.
1948 (Mar qtr): Son born, second marriage.
1949 (22 Oct): GRM imprisoned as Gordon Rowland MARKERSON, Armley Jail (Leeds), for bigamy.
1950 (9 Jan): GRM released from prison.
1951 (Mar qtr): Son born, second marriage.
1956 (Sep qtr): GRM attends Aylesbury wedding of eldest son from first marriage. Not seen again by him.
1958 (Jun qtr): Phyllis MARKERSON nee OAKLEY remarries – new name CHOWNS.
1971 (26 Mar): Dies as Gordon Richard MARKINSON (retired railway platelayer), Leeds. Second family believe he had worked for the GNER.
1972 (Dec qtr): Death of Phyllis Emily CHOWNS formerly MARKERSON nee OAKLEY, Oxford.
1975 (Mar qtr): Death of Norah [sic] MARKINSON, Leeds.