[gee6]

Looked at your other photos sent via PM, but not entirely clear on the "look down" between power steering resv. and airbox. The angle is obscured by the reservoir. Anyway, I zoomed in as much as I could and I believe that loose wire should attach to the inboard of the 2 studs there - if there is nothing there now. I cannot tell if anything is already there, or even if there is a nut missing off that stud. Just be sure that the other end is only attached to the engine block as you stated.

 

[gee6]

find a suitable position on the frame, clean to shiny metal and bolt it down,

Shouldn't be needed if we have identified the provided earthing stud. Clean up, certainly, before securing since the vehicle has been in for repairs (overspray, etc) then a dab of battery terminal grease, silicon grease or vaseline to help keep rust away should do. KISS

 

[gee6]

OK, so not studs but bolts. (Securing the ps fluid reservoir?)

 

[gee6]

Good luck with both