I ordered some Hawk flight stands came to about £15.00 for 16 stands. Which should be stable enough to hold the asteroids.
When you compare them to the War Rocket Class Rocketships you get a reasonable idea of the size of each piece of floating space rock.
All together this comes to around £30.00, which feels far more suitable.
Lets just hope they don't fall to bits when I drill the holes, still worse case I guess they can always go back on the BBQ should we every get a dry day again....