Removing a seized on electromagnetic clutch from Countax D18 50?

Hi, I have a Countax D18 50 mower. The Electro magnetic clutch has busted and I am trying to get the old one off. I used a 3 point puller on the bottom half of clutch. The bearing and housing came off easily but the top half is stuck.
There is nothing for the 3 point puller to hold onto so I don't know how to get the top part off without angle grinding the unit in half. Before it broke the unit was running red hot with friction between the touching plates so the top bearing is probably heat seized.

Any ideas?

Many Thanks
Nick