Hi
I'm having a real problem stripping down the forks on my 1G1 model.
The Allen bolt at the bottom just spins, even with an airgun and the forks compressed. On my XT600, you simply fabricate a locking tool on the end of a metal rod and lock up the damper gubbins.
Any suggestions?

I have always used an impact driver with an Allen Key Socket , and with the forks compressed .
Never failed yet .

Grind a tapered end onto an old hardwood broomstick and tap it into the top of the damper rod.  The zip the bolt out while holding the stick. 

 

Picture might help...  grind or whittle a gentle taper on end of stick that's small enough and tap into end of damping rod.

 

Or if you have deep pockets, Racetech sells a tapered aluminum tool that works the same way

Heat can really be your friend on these too, I've had good luck leaving a heat gun on high about 1" away for 20-30 minutes. May discolor the finish though, but it does help a lot.

Mark T's trick always works for me. I also find holding the fork tube extended with held pressure pops the bolt loose using an impact.

Unfortunately I have tried the wittled stick method and it doesn't grip onto anything at all. In fact, when I try to look down the stanchion, there doesn't appear to be a cup or a hole at all...more like a raised platform. I'm getting anxious
Also ... after I've removed the fork seal circlip and retaining washer, should the stanchion slide out of the lower tube with a good tug, bringing the seal with it?

We didn't have that model in the US but normally seal does not come out with the tube.  Also, someone may have swapped forks with a much newer model or something...  I don't recall seeing the older style Yamaha damping rods without a hole.  Even the newer bikes with conventional forks have a hole in top of damping rod.  Maybe you just haven't whittled stick small enough.

Can you post pics?

Thanks 
I’ll post some pics tomorrow

In your first post you mention the forks are compressed, I always leave the spring in and the the top bolt in and out the forks extended, the spring pressure helps hold the dampening rod, then I use an electric or air impact gun on the Allen bolt and it zips loose every time I have tried, probably have rebuilt 25-30 sets of forks.