Yes - no point in spending £25 on a branded retro fit anchor.
If you live near to a Blacksmiths or Metal fabricators, get them to bend some large diameter solid section stainless bar (or do it yourself if you have the equipment) over the end of an anvil or 60 ID drift. Make the tails about 500mm long and weld some flat plate to the ends of the 'loop'. Dig hole, place loop in ground and fill with conc.
Make sure you paint the end of the loop in a bright colour so folk don't trip over the newly made man-trap!
Millions of other ways to do it..............