Find my Past have service records for John George White. Quite a lot of pages, but the synopsis being: John George White (later shown as born 30/5/1894) was born 1893, presumably 30/5/1893) and enlisted in Coldstream Guards 8/9/1914 at Fulham regimental no. 12417. Definitely your man because lists his wife as Dorothy May Winifred Lawrence, married 7/3/1914 and then shows 2 children: John Richard White born 16/7/1914 Margaret Louisa White born 2/1/1917. When enlisted was a Painter, born Hammersmith and address 53 Stirling Road, South Acton. He was transferred to Labour Corps. 3/10/1915, regimental no. 641388. Discharged 21/8/1918. Also details his wounds on various occasions.
Possibly the John George White birth reg'd Sept.qtr.1893 Fulham, mmn Coombs. If so, his parents were Edmund Joseph White and Clara Elizabeth Coombs although I can find no marriage between them. However, no use relying on conjecture - one needs to have proof and I believe you definitely need to get the 1914 marriage certificate to confirm the couples respective fathers' names and occupations. Alas, no full details of the marriage available online (may well have been in a register office). If I've identified the right parents none of their children appear to have been baptised, possibly because they had never married.
Annette
The dau. Elma I. White birth Mar.1926 Hammersmith.