If you are 45 now and still haven’t met the people in charge yet, that is a pretty sad state of affairs! LOL
Seriously though. If you go to any place regularly you get to know some of the crew members. The guy(s) at the door, their current DJs, the (head)bartender, regular hostesses, etc.
Once you know them, just ASK! Ask who the guy is that organizes/books those nights. And ask them how to best go about approaching this person. Can they introduce you? Is there a certain way this person likes to work (personal contact, mail, dropping a demo mix, etx.) and if so, can they help you get your message to this person.
You get my drift.
You will surprised how much people are willing to help if you ask them nicely.