Houses owned by a trust cannot qualify for the main residence CGT exemption.
I don't know if there is a land tax exemption for a residence held in a trust if the beneficiary is using it as the main residence. I don't think there is but could be wrong, but you are not the sole beneficiary of the trust so you wouldn't get the full exemption. Give OSR a call and see what they say.
You probably didn't anticipate moving into the property and that is why this has happened. You would probably have to transfer the property from the trust to your self to fix this which will be costly in terms of CGT and stamp duty.