Interesting Career

I've been trying to piece together my grandfather's military career and it has turned up some interesting things. He served in the Royal Field Artillery from 1905 to 1919 but his duties varied.

• From Aug 1914 to 1915 he served the 40th battery, 43rd Brigade.
• He received a field commission to 2nd Lt
• In May 1916 he was sent to review the AA batteries around Liverpool and remained with them until Nov 1916. During this time he acted as Adjutant of the defense batteries.
• With AA experience he was called back to the RFA and sent to Paris to command an AA battery
• In early 1918 he was loaned to the newly formed Royal Air Force to manage payroll. While with the RAF he wore a RAF uniform and was trained to fly. He was also promoted to Capt. The RFA requested his return but the RAF said that he was too important in his current position so they refused. 
• His career ended in 1919 when the RAF was disbanded. 
• Attached are some documents