Hi Deadflesh,
Great to see that you are concerned with the turtle's health. There is a caresheet located at
http://members.optusnet.com.au/~expansa1/ that may be of assistance to you.
To be perfectly honest, the turtle looks in top condition from what I've seen in the photo's and there is nothing to worry about as far as the tiny scratches on it's shell or shell rot at all. Can you take a pic of it's plastron (underside) and tail for me and post it?
Just one other question, do the EPA know that you have taken someone's turtle that you believe weren't looking after it as they were meant to be? You may be leaving yourself open to a lawsuit (which you may not be able to afford) for taking the turtle. Agencies like the R.S.P.C.A or EPA/QPWS/ ECOACCESS are the only ones in QLD that have the power to take a reptile from someone without being charged for stealing.
Also, if you are having difficulty with finances etc, best to contact a carer or association with the financial backing and long term experience to help with your situation and look after the turtle.
Kind regards,
Craig
Australian Freshwater Turtle Conservation & Research Association
www.aftcra.org.au