I feel for you - been in same situation and simply gave THAT one away.
Could not afford to stay there - even if I did love the work.
Gotta eat, and save enough to think about a family.....at the time.
I guess you are aware that if 80% of your income is from the one employer - you are no longer a 'contractor' - you are deemed by the ATO to be an employee - and as such, are entitled to employee conditions and have your tax deducted by your employer.....plus 'super' etc
I think the above is fairly correct - others may be able to 'fine tune'....
Good Luck
