Dude.....
Took my first flying lesson in May 1991. Started at age 31. Like you, I had a full time non-flying job. Left that job when I got the gig in BKK (not Bankstown).
"I am aiming for something like REX, Aeropelican or Horizon"
On this statement.....Don't limit your oportunities. Look outside of the box (ie. Australia)
Pint o' Pale
"Single mindedness" is an understatement.
Good luck