Ahh ok. I was typing up my last reply at the same time you were 
All I can say is…good luck, and make the most of what you have vis a vis current qualifications, passes, etc.
Or, if you want to move out of the airport transport side of things, research the ■■■■ out of what you DO want to do.
Google is very definitely your friend.
I just googled “Career path to ADR driver” and it gave me all the info I needed. Just as an example.
Very best of luck, hoss.