I can't remove the driveshaft from the hub.  I've tried wedging a breaker bar amongst the wheel studs and turning the centre socket, a rattle gun at highest setting and soaking the nut in WD40 over three nights.  My brother stood on the axle whilst I put my weight on a breaker bar to remove the shaft.  Still no luck.  It's on bloody tight.
 
Any suggestions?
 

put it back in the box, apply handbrake and put into gear, then try and rattle gun it off.
 
You may need a better compressor if you only have a little one to

Unfortunately its part of a driveline thats already out of the car.  Compressors a real one 15 amp cast iron.  Ta for the idea.
 
 

Badly phrased but basically no car just driveshaft.

Get some av-gas and soak it overnight. Then use a rattle gun.
Av-gas soaks deeper then WD40.

Where do I get av gas? What about specialist lubricant penetrene?

About a metre of heavy angle iron bolted to the hub flange.   On floor.   Inch drive socket and metre and a half of pipe.  Has always worked even on a lot bigger tighter b###s#ed things than axle nuts.