For these bars to be removed fairly easily and SAFELY, the suspension arm must be in the right place otherwise the torsion bar will still be under load. Undo the shock absorber and try lowering the arm gradually (not putting too much stress on them), until the bar comes out. You should NEVER apply heat to suspension/steering components as you can seriously weaken them. Mark the bars with a dob of paint as a starting reference point so if it does go all T1Ts up, you can put it back to how it was.
Another tip: When refitting the bars after lowering/raising etc, the bars have a different number of splines on either end. Dont just hammer them in, keep turning them one spline at a time until they slide in easily. Dont forget to clean and lube the spilnes!
Hope that helps.
Bob RTE