The correct way to remove the camshaft?
 

I'm playing around with my spare engine, I used a slide hammer and M6 threaded rod to pull the rocker shafts which was pretty straightforward.
To remove the cam I used a flat bar and drilled two holes which aligned with the sprocket bolt holes and passed M6 bolts through the holes with nuts on the back. The bar had hole in the centre and the slide hammer was attached to that. A couple of strokes saw the camshaft out.
It seems a bit of a faff, is there an official way to do it?
When it comes to refitting I don't fancy hammering the cam back in, what about heating the bearing holes in the head with a torch so that the cam bearings just slip back in?

Put the head in the oven at 60C, put the cam in the freezer for 30min, you will then be able to fit the cam back into the head with no force by hand.

Thanks, pretty much as I figured. So with the head still attached a hot air gun should do the trick.
Is the way I pulled it out the simplest method? I'm surprised there isn't an internal thread on the cam to allow a bolt to be threaded in so a slide hammer can be used.