Gen 3 rear hatch stopped unlocking.

The rear hatch latch/lock refused to open on my gen 3 outback. Removing the trim and opening manually with the white plastic lever revealed a nut sitting in the lower catch area on the floor side. Does anyone recognise it? Has it fallen off a part of the latch?

The latch won't lock/unlock with the fob but the white lever does move up and down with the fob. The 'hook' thing that actuates in the lock is in a position now where the rear hatch can't be closed, shown in photos.

Is there a specific bit size for the lock to hatch mounting bolts? They are almost stripped already so I have not been able to remove the lock for a closer look.

Yes, I have searched and read previous threads.
Any help appreciated, Thanks!