Hi Guys, great to read all the good advice in this thread.
I just wanted to put this one out there for information and comment. This is a recovery point that fits in the Hayman Reece square hitch receiver. It's made with 50x50mm mild steel x 6mm wall thickness. The recovery hook is the standard type available from 4wd shops (buy from a reputable specialist), held in place with hi-tensile bolts. You'll see that each bolt has two nuts securing it; one inside the tube holding the hook in nice and tight, and a second nut outside the tube. A friend with engineering qualifications (RAN) described this as a double-shear configuration - each bolt would have to be sheared in two places for the attachment to fail (x two bolts). Similar configuration with the tube held in the square hitch receiver - the pin would have to shear on both sides for the fixture to fail. In practice I'd expect the chassis or the towbar itself to fail first.
I prefer this to the steel block and shackle fitting that is also designed for the square hitch receiver, as I've always worried about putting shock loadings on a shackle. I've been warned that shackles are rated for a static pull (or lift) rather than a shock loading. Happy to take advice on that one. Personally I'll always try for a gentle tug recovery first, and then use the winch rather than go for the "hero" approach. All those videos of snatching incidents are very sobering! Cheers!