The aim was to fit a proper recovery hook to the rear of the zook rather than the factory tie down. I wanted something that would sit under the tow hitch frame. This is what I've done.
93 Nissan Pathfinder recovery hook.

Ground edge at bottom of picture and drilled hole 110mm from original left hand hole.

Existing tow hitch mount

Hook fitted side shot

Hook fitted look up shot

My options for further strengthening are;
1) Drill 3rd hole in tow hitch bracket and chassis to fit a bolt thru the (now) middle hole of the hook
2) have the hook welded along the two long contact edges with the tow hitch bracket
3) do both
4) abandon the entire idea as nothing will stop it being a death trap to myself and others.