the anchor point on the photo is indeed where the tow bar and or jate ring bolts on. It appears that there's a tow bar fitted before on your disco...
to get it off, you've got 2 choices:
1) heat the anchor point using a blow torch, then either using a hammer or a locking plier and try to wiggle the bolt out.........BE EXTRA CAREFUL WITH THE BLOW TORCH, AS FUEL TANK IS NEXT TO IT...
2) use a hammer, and an old + screw driver......try to punch the bolt out the other side.......you wont be able to move the bolt out the other side totally as fuel tank is in the way.....however, once you've started the bolt moving, they can be pull out with a locking plier.....
I went for option 2 earlier today when the bolt head snapped, while removing the tow bar...