File WO/391 at the National Archives is a month by month listing of the London Gazette entries for WW1 DCM awards. Importantly, an Army clerk has added the Schedule Number and the place and date of the DCM action in pencil on the original entries.
The London Gazette entry for Robert Jones' DCM has the place recorded as "Combles-Fregicourt".
The date of the action is given as 29 January 1917.