I was guessing at the rocks size, so could be over egging it a little bit. "The fish was this big!" It might actually be half a meter on the longest axis
Fishes, ill look up these screwbolts with rings as they sound good!
To get going I need to be able to shift some bigger rocks on the surface, but being able to release some gravity on them should help. Then I can start to think about others and whether I split them.
It's not in an isolated spot being 10-15 mins from a parking spot and not far from the nearest town.
If need be I'll:
-borrow a shunt of someone to stop the rope being chopped
-Grab some slings as sinker suggests
-Use multiple anchors as fisher suggests with the club tirfor.
-Add some ground anchors into the mix for the static part of the haul with a "big knot". (2 hangers + 3 ground) should even out the load, if it needed it.
Then if all looks good I'll move onto employing other things like scaff tripods, buckets, cargo nets. But at the moment I'm only at the stage of ooh I like the look of that I'll pull some more stuff out.