Hylton said:
"As already pointed out in the first reply to your question, the person standing up is wearing a Royal Flying Corps jacket. This style of tunic was known as the “Maternity” jacket. The fact that it is fitted with shoulder straps indicates that the photo was taken after June 1914. This style was then worn throughout the remaining period that the RFC existed, up to their integration on 1st April 1918 into the newly formed Royal Air Force. Shortages of resources in fact resulted in some men continuing to wear their Maternity jackets well into 1919. You say that your friend’s granddad was an Observer or Pilot at some point in his career. It has to be said at the time that the photograph was taken, he had not achieved either of those accolades, as he would have been wearing on his left chest one of the two distinctive badges that denoted those qualifications.
Additionally it is to be noted that the number on the dogtags (63356) was not allocated until Feb / March 1917.
I hope this helps a little. Hylton."
It certainly helps a lot, kind sirs! Thanks for all the information you posted here. My friend Jack will truly be grateful for this.
-RODION