Thank you both. I think you have him sorted.
On the matter of his using his Captain title after the war, I read that it was disapproved of but not illegal. I feel it was a bit presumptuous given the number of active Captains who died or were disabled. I don't know how it went down locally - there were a number of fatalities, mostly privates, Sergeant being the highest rank.
Wherever you read that honorary rank was disapproved of is wrong. The same Army List for 1916, which Shaun linked to earlier in this thread, explains the official situation on page xi: https://archive.org/details/monthly-army-list-1916-dec/page/n54/mode/1up
Yes you are correct. No strictures against using any rank above a certain level after the wars. Some kept them as they continued to be involved in military matters in peacetime and others did not. Some used them according to the circumstances ie when say making approaches on behalf of returned service people to Govt they would show the rank, when hosting talks, officially meeting envoys of nations that either fought with them or against them.
I'd hate for my officer uncles (Major, Wing Commander, Captain) several of whom were older, some who remained here in NZ (Gunnery Instructor) and some who went overseas as older soldiers S/Sgt and two L/Cpls (both killed one in each war) and some who'd gone up through the ranks (Major, Wing Commander, Captain after TFR) to be dealt with in this slightly dismissive way apparent through here.
I'd hate to see it come through in a write-up about their service filtered through a lens of 'only overseas service counts/'but Mummy what did they do' and 'officers don't count''. Not one of the military men in my family ever, ever cast aspersions on where/how their fellow combatants served or their rank per se. Whether they liked them personally or felt these people were good at their jobs different story but based on rank, no.
That they served was the key and a bond forever.
This may sound a bit harsh but I'm going to say it anyway......hopefully the write-ups will be edited, peer reviewed so that contributions are recognised no matter what the rank or the theatre of war served, officer or ranks etc etc.
Hopefully a bland, plain but informative history is given.