I suspect it would be much cheaper to go aftermarket than OEM...
AOR/Ramy Automotive have 2 options, a hidden (similar to OEM), and a larger open winch cradle that provides for a wider selection of winch options.
Ineos Grenadier Specific: Designed for compatibility with your off-road vehicle.Strong Steel Construction: Offers a reliable base for your winch.Streamlined Integration: Maintains the clean and rugged look of your Grenadier.Double-Check Compatibility: Verify fit with your specific model year and...
www.ramyautomotive.com
Custom Fit for Ineos Grenadier (2022-2025) – Designed for a precise, secure fit with no drilling required.Heavy-Duty Steel Construction – Built from high-strength steel for maximum impact resistance and off-road durability.Integrated Winch Mount – Supports mid-size winches (8,000 - 12,000 lbs)...
www.ramyautomotive.com
With shipping it's under $1500 AUD + duty
Otherwise it's something like Offroad Animal for a full bar