fsck_hfs / DiskWarrior repairing - Invalid Node Structure / Invalid Record Count

I am struggling to repair a hard disk with Invalid Node / Invalid Record Count errors.

This is the hard disk in question:

I have tried with fsck_hfs / Disk Utility:

And with DiskWarrior:

With DiskWarrior I cannot Replace, or Preview the changes as the buttons are greyed out.

There is a single partition on the hard disk. I cannot mount or repair it. Is there any way of me repairing this disk or recovering the files?