Dear Ken,
I also think there isn't a marriage to be found for James Matha Beaney; either, to your grandmother Amy or to Georgina.
The online electoral registers do not cover the years 1911 to 1920 to see where James and Georgina might have been living, however they were both living at 152, Victoria Street, Mansfield in 1921 up to 1932.
I see from a newspaper report that Georgina's son (sometimes known as James or Bernard) was in Mansfield by at least 1913.
Nottingham Evening Post 18 August 1913
Mansfield Woodhouse Motor Fatality - Bernard Beaney , 139, Victoria Street, Mansfield, who was driving the float, described what occurred.........
I have also sent a pm.
Kind Regards
Sheila.