G'day Moocha,
I'm sure there are historical threads that deal with clutch replacement but I'm struggling to find them with the search function. I'll keep trying.
It's a long time since I took a transmission assembly out of a tractor and will need to go and refresh my memory in the shed tomorrow but from memory the only real 'issue' is removing other stuff to allow the assembly to be removed from underneath (lowered out of the machine). Like I said it's been a while but the clutch fork and it's mechanism needs to be removed and the entire cutter clutch pulley frame. Both are removed with a few bolts and then the bolts that hold the flangette's that hold the transmission shaft are removed and at least one of the bearings needs to be slid along the shaft (grub screw secured bearing retainer needs to be loosened) to allow the assembly to be 'wriggled' free and down. Rust on the shaft may make sliding the bearing and retainer a bit of struggle. Penetrating oil and fine emery paper is the go here.
Of course all that is from memory. I'll have look in the morning.
Can't help with the anniversary machine as I have no experience with them......but someone here will know

Cheers,