Are there any special considerations putting a ground anchor in a wall? I don’t imagine so but want to check. It’s a breeze block wall with no access to the other side except via someone else’s garage.
What’s the weakest point of the setup?
From your brief description I’d imaging it’s not the anchor, or the chain but the breeze block, especially if you’re using an expanding anchor.
The easiest attack would be to put a bar through the anchor, apply leverage and try to get the bolts to crack out of the block (bear in mind they’re probably not too fussed about damage to your property).
Withstand might be improved if you used a resin anchor (someone else more knowledgeable will probably pipe up) but if you can anchor into a concrete slab (such as the floor?) It makes plain old leverage a less viable attack…