mmm, I assumed that it all swapped over form a left to a right hand drive, but it obviously does not as your bonnet release is still on the left side....

Which side is your interior fuse box ??

If its on the passenger side, remove the passenger side panel and you will seee some obvious ground studs.

If you dont want to do that, those 2 bolts in the top left of your picture, either of those would be ok to add a ring terminal and wireto and use as a ground. Would be best to use a small bit of grit paper, or sand paper etc to remove the paint under the bolt head. but they would be ok to use.

 

The fuse box is in the area below the steering wheel.

I believe I found the ground stud. It looks like there are four black wires going in to a harness that is clipped onto a stud beneathe all that wiring in my photo.

I think I'll try grounding there.

Thanks for all of your help!

 

That is exactly the spot. I thought it would be under the bundles of wires in your photo. The "key" here is they are all black wires. On Disco's, the grounds are black wires.