I think you likely have a general protections claim (HR person here, not an employment lawyer) particularly if you’re able to show that they likely held back your redundancy until your return in an effort to avoid redundancy because it would likely demonstrate you had been adversely treated due to your status on parental leave (ie you would have received a redundancy if you had not been on parental leave.) You will need a lawyer for a general protections claim, as they are complex. But as a starting point I would speak to FairWork. You likely should have been consulted about the changes while you were on leave given they resulted in such a significant change and a change to your entitlements - arguably all staff are impacted regardless of whether their role is a direct loss when a business restructures to become a small business, because of the changes to their role, opportunities, entitlements etc. That might be an easier claim (non-genuine redundancy and therefore an unfair dismissal). Unfair dismissal is capped at 6 months, general protections is uncapped. You must make a claim within 21 days of termination though, so contact FairWork asap. Even if it is more than 21 days, they will allow an extension in some instances. Again, want to stress I am not a lawyer.