Hi - Did you check where the regiment went to between 1911 and 1914 where he might have married?
There is a lot of information on the internet via Google about the 2nd Dragoon Guards Queen's Bays, 1st Cavalry Brigade, including a number of books written about the regiment. Information includes: "Regiment landed in France & Flanders 14th August 1914 as a component of the 1st Cavalry Brigade. Remained in France & Flanders for the duration of the war. Moved to Palestine July 1919 and on to India 1920". [www.northeastmedals.co.uk/british_cavalry_regiment/2nd_dragoon_guards_queens_bays.htm]

Which raises the questions, if he stayed with the regiment he was with in 1911 could he have fathered those two sons when it was unusual to get leave so early in the war (John C Kinvig Farnham Surrey 1915 Jul-Aug-Sep), or would he have changed to a different regiment for WW1 (seems unlikely)? You said in an earlier message that you had two pcs written to his sister during WW1 - sister's name? Any other info?

Also, are you sure he wasn't the other John Kinvig (fisherman, b.Castletown) who said he was aged 26 in the 1911 census, but he could have increased his age because his Irish wife Eileen was several years older than he was? He had a son Norman, b.c.1907 Castletown, and daughter Dorris's birth looks like Emily Doris Reg. District: Toxteth Park, Lancs, 1905 Apr-May-Jun.

Sue