TT, take LeadSled's advice and contact Arthur Pape. Something in what you are saying just does not ring correct. I was recently approached by a guy up north who was very much in the same boat as you. Doing his PPL and couldn't pass the Ishihara (like 8% of males). He got his medical back with the restricion I mentioned earlier ie, Valid in Australian airspace only up to CPL. Therefore OK for NVFR, OK for IR, OK for instructor rating.
Out of interest, do you have your medical yet?
I ask the same question as Andy RR, has something changed recently in Australia and CASA's rules?