On retiring from his civvy job aged 60 my father moved back to village where we'd lived until I was 18. He styled himself Mr Artist on his cheques etc, but most of the village (large ex-Service contingent) insisted on calling him Captain Artist, RN Rtd. Those who clearly had a copy of the London Gazette or the Navy List would put in his CBE as well, which he was even more reticent about.
Not forgetting that post WW2 lots of people left the military with quite junior substantive ranks who had held much higher acting ranks. My FiL was an acting Major shortly after he made substantive Lt.