Such fond memories of those and yes they are in there chuffing tight.
I have seen oxy acetylene used but a bit hot for my liking but I did use a plumbers gas torch.
I also considered chopping off the two bolt hole lugs and then putting a socket or spacer over the ball joint and pulling it out with the nut and a washer but may have just pulled the ball joint out.
From memory, in the end I heated as much as I could and hit it with a club hammer without deforming it so it wouldn't go through the hole and I used a cold chisel under each lug and hammered that to lever the joint apart.
I may have started the gap under the lug with a dremel wheel but care needs to be taken to not damage the hub.
It was heat, hammer, chisel , repeat
I have seen it done quickly with oxy kit but didn't want to put too much heat into the hub and wheel bearing.
I think I may have some fots somewhere
Clean up the taper really well and grease with copper slip before reinstalling the new one.
It does feel like it will never move
When hammering the back of it I hammered it slightly towards the centre each side so it gradually folded inwards slightly rather than bulged out
