Girder fork headset bearings

Next project on the 16H is to fix the head bearings. Checked yesterday and there is too much play although no 'clicking' on turning the bars so I don't think the ball bearings are worn out.I loosen the head clip bolt, but the top nut above the clip seems to be hard tight. Is that correct, please? I expected the clip to be adjustable up and down. I don't want to strip it all down unnecessarily. Could the nut be thread bound - and if so, how come? Have I failed to loosen something else?The other issue is that I still don't understand quite why the steering damper knob can be unscrewed about 3/4" and then turns uselessly as it is still retained somehow. I expected te rod to drop out on top of the mudguard but it doesn't do that. The drawings in the usual books are a bit vague.ThanksDavid