After retiring from the RAF I went on to manage a department at a UK Airline, quite a lot of the guys around the HQ were ex RAF or Navy; Two of the Fleet Managers, some of the Safety Pilots, a lady in Flt Ops Project Management, the Safety Manager, even the Airline MD. All super, super people, all had been commissioned, some had been fairly senior, not one of them mentioned a rank.
My direct boss there had retired as a Sqn Ldr navigator on Tornadoes, but I only knew his leaving rank because I asked once out of interest, he wouldn't go on about it. The rest of the ex-forces people were nearly all RAF/RN pilots which I knew from the odd dit in the pub, although I have no idea what rank, they seemingly never needed to mention it. Which is as it should be, we were working for an airline then, we were no longer in the RAF or RN and we'd each gone off, retrained, reinvented, and come into a new career. I liked knowing they had a forces background but it wouldn't make a difference to the professional respect I had of them.
I think it's a little pitiful to try and maintain a rank once you're out. You're out, let it go, become the new you.