Hi,
You may have already known this but in case you don't:
Thomas Bestford served with the Royal Engineers as a Sapper, entering theatre (Mesopotamia) Feb 1917. He was commissioned on the 4th November 1918, to 2/Lt. At some point he is promoted to Lieutenant. Along with the Victory & British War Medal, Thomas received the General Service Medal with the Iraq Clasp, as he went on to serve in Iraq after WW1 (presumably the Iraq revolt).
George Bestford was a Sergeant in the 20th NF (1st Tyneside Scottish), his number was 20/21 meaning he was the 21st man to enlist in the Tyneside Scottish. He is wounded, at which point I believe he was transferred to the 25th NF (2nd Tyneside Irish) and is then commissioned to 2/Lt (I don't know the date). He goes on to be promoted to Lieutenant whilst attached the the 9th NF. He is at some point again transferred but to the 2/4th Oxford and Buckinghamshire Light Infantry. I have attached a photo from the Illustrated Chronicle. Along with a paper clipping of him being reported wounded - Newcastle Journal 12th July 1916.
I have also attached a newspaper clipping relating to William Thomas Bestford - Newcastle Journal, Friday 28th July 1916. Along with a photo of William from the Illustrated Chronicle.
There is an Adam Bestford serving in the Royal Engineers, (n. 1248 & 459201) - possibly your man?.. I can' t find any evidence at the moment to link Adam to your Adam.
I have also found a William Bestford which I believe is their cousin. His father is William, brother of Thomas (father of the 6 boys). He served in the Northumberland Fusiliers (n. 19530). He was discharged 21st Feb 1918, residing at Bedlington Colliery. I have also attached a photo from the Illustrated Chronicle.
Many thanks,
James