Hi,
I really don't know if he continued his military service  - 
I don't have full access to Pension papers etc so am presently gathering as much information on him as I can which might help predetermining if the information in pension papers would be useful or not. 
I know very little about pension and attestation papers - Can I ask  - at what stage in his life / career would pension / attestation papers be drawn up ?
In 1911 census both Arthur and Philip were student teachers.
His father served in the Royal navy  - both Arthur and his brother Philip J. ( sometimes James P.) (and possibly brother George) served in WW1 and were both Liuet in RFA.
From Arthur's medal card his forwarding address was to B. Guiana c/o "the Rupununi Dev. Company" - on the card however this was then crossed out and the new address was c/o "J. Balasch, 4 Robb ST, Guiana, BG".
As far as I understand the Rupununi Company was setup with the support of the Colonial Government of Guiana and capital from British Business men.
based on this I was of the opinion that he might have left the Military - 
Can I ask  - is it normal to be considered / addressed by your military rank ie : Lieutenant A J Going from British Guiana at complimentary dinner in 1924  - if you had already left the military service ?
B.