Using titles after retirement.
It is easy to ridicule ex-officers who sometimes use their rank titles. However, it is officially sanctioned and used to be the norm not so long ago. It is only in the last few decades that it has become contentious. I don't think it is anything to do with snobbery. Probably more to do with pride. Professional pride in ones lifetime achievements, in ones service, in ones unit, in the comrades with whom one served and soldiered.
We carp on about the public not recognising our worth as servicemen, so why be ashamed to acknowledge what we are/were? No one criticises those retired personnel who attend events, reunions etc wearing military symbols such as blazer badges, ties etc. And if a retired doctor, professor, clergyman can still use their identifying title, why not us? Nothing to be ashamed of that you were a professional soldier. If some do tear the arse out of it, that's life.
The public stereotype of a retired colonel or other middle/senior ranking officer is of a blimp. That is because they never knowingly see the real thing, just what appears in Miss Marple, Poirot or what have you on the box. Look at photos of real colonels or blue equivalents in the news: they look like boys. They command a batallion or equivalent in their mid/late 30s and by God they are good at what they do. And they are not a crock when they retire at 55. If Joe Public knew who and what you were, their stereotype might change for the better. So don't be ashamed of using your title on the appropriate occasion.