i took my crank arms off yesterday the non drive side came off a piece of piss but the drive side was stuck like yours, i used oxy and accetylene gas bottles in the end .put old bolt in shaft and wind in leaving enough of a gap to fit nozzle then warm up little at a time (dont get to hot because of alloy spider) i put arm across vice and tapped with a hammer on bolt and after a couple of goes i came out i think heat will be better than force as i have seen shafts break!!!