Do you mean bolts with a hex head, i.e. hex bolts?
Correct, hex bolts
I have the attachments for my drill and I just tried to drill them in to the wall plugs but the drill bit just spins and the chuck unloosens, not sure what I'm doing wrong there
You tried drilling them into the wall? And the drill loosens the chuck?
It doesn't do this when not under tension?
You've pre drilled where it's going in right? What are you drilling it into?
Is the hex attachment the exact correct size for the hex bolt head?
Anytime I’ve seen this happening it’s one of 3 things;
1. Hole drilled is too small in diameter
2. Hole drilled is not deep enough
3. Drill being used does not have sufficient torque to drive it
If 1 and 2 are definitely right, then you should be easily able to drive this home with either a decent socket set, or drill with enough torque.