Rear brake plate., Help needed.

I tried to adjust the chain on my RC36-1 the other day, but could not get the hub to move.

I figured it was time for a hub strip and clean, because I have heard the horror stories about detritus inside the swinging arm.

The first part of the job was easy enough, but I hit a stumbling block when I got to the hub retaining circlip, this took absolutely hours to remove, because it was seized solid, I had to get brutal with all manner of tools to get it off.
The next part again should have been easy, pull the rear brake plate away...

This is also corroded in place.
This must be why I couldn't adjust the chain, with the torque arm attached to it the hub couldn't rotate.

I have now spent hours trying to remove it, I have used a selection of hammers.
I have hit it around its circumference, hit it from both sides, hit it with another hammer placed against it.
I have hit it using a drift in multiple places, I have used as much heat as I can get from my spindly little torch.
It won't move and now my arms feel like lead.
Am I the only person to have this problem?
This stage of the job should have only taken a few minutes, it has taken me hours.

Any suggestions, anyone?