Dave et al,
If you find the flange does not want to come off the shaft, get a piece of 1/2" steel plate, drill four holes in it aligning to the bolt holes on the flange. Place a 7/8" or 22mm socket between the shaft and the steel plate, put some bolts in that you never want to use again and tighten the whole thing up.
You may even bend the steel plate, the bolts will stretch
but eventually that flange will come off - it has to and none of the important parts will be damaged.
Seafever SM 425
PS - it's a couple of years since I did this, so my memory is rusty if so someone please correct me.