Re the carrying on of rank, I understood that senior officers could continue to use their rank as a title. So Sqdn Ldr and equivalent.
I was introduced at a function once to an elderly gentleman, 'Captain ****'. I asked him what his role had been in the Navy to which he brusquely replied 'Royal Logistics Corps actually.' I didn't press the point that he perhaps shouldn't be using the title 'Captain.'
Those who didn't achieve such exalted heights before leaving should never try to boast of their stunted attainment afterwards.
Cruel but I feel I shall file that one away for future use...