You on about the m16 spline socket on the rear?
They're a spline because theresvery little room in there to geta normal socket on there.
The only way to get these off on axle stands is to drop the rear hub so you can lift the top arm out of the way and get some leverage, alternatively if you can get the car about 3 ft up in the air with a proper garage jack then assuming its properly safe to do so you can get a good old 30" breaker bar with the spline socket and they'll come straight off.
Don't persevere with trying to get them off with the car at low level, if you round off the internal splines on the bolt the hub will have to come onto a bench and then you'll have to grind them off.
So get it high in which case dead easy, or undo the top arm and bottom arm suspend them out of the way and get leverage that way