I urge caution before accepting the CASA offer. It may not be the olive branch it appears to be - your case may be getting a little "warn" for CASA and they are offering a way out which gives CASA the greatest chance of success.
An Ombudsman's decision may also be prejudicial in any subsequent Court action?
I'm not a lawyer but the ADJR Act may be a consideration for you?
https://www.legislation.gov.au/Details/C2017C00238
Here is an explanation:
https://www.mccullough.com.au/2018/07/10/good-government-keep-up-with-your-admin-law/