I've unscrewed the allan key nut inside the steerer tube – shouldn't the 1" stem just lift out? Should I hit it with a hammer? Opinions please…

Hit it with something big.

You have to do that to knock the wedge out and loosen the quill.

Loosening, then tapping the top of the bolt normally frees the wedge, and then the stem will lift out. I assume the bolt goes down through the top of the stem (ie, it's not some bizarre system the bolts up from under the crown)?

Did the bolt rise up as you undid it or remain in the stem?
If it raised up as you unscrewed it, put it back in and hit it a few times till it goes down.

The bolt is completely unscrewed and didn't lift up as it loosened. I've just battered it with that massive wrench on the black rag in pic 2, but to no avail.

V annoyed with self as just had the whole assembly in bits to replace headset not long ago.

EDIT: done – hit the allan key with a hammer, straight down and the whole lot fell apart. In a good way 🙂

Cheers all!!

Nice wallpaper.

I haven't forgiven that wallpaper for taking up five hours of my life when I was trying to give up tabs. Nearly killed my wife and dog. Still off the tabs though…..

As above put the bolt back in and screw it back into the nut then belt it one and the nut should pop out the stem and the bolt will drop .Hopefully the stem will then come out .I reckon the nut is wedged in the stem .Have a look down it forst before you put the bolt back in.