I'd just use the M20 x 1.5 mm bolt method.
I used to use a similar method once to remove the bronze spigot bushes from the back of car crankshafts. The hole in the back of the crank was filled with grease and a dowel that was a tight sliding fit was hammered into the hole.
Hydraulic pressure forces the bush out .... in theory. The method works but can be hit or miss. Eventually I started tapping them with a thread and dragging them out with a bolt and slide hammer.