Robin, a good heat gun is your friend when removing stuck liners. When dissassembling an engine, I remove the head and back plate. Mount it in my test stand and put a prop on it. I use a small piece of plastic in the exhaust port for the piston to push on the sleeve with and if it is a stubborn and stuck liner/sleeve, I warm the cylinder up with a heat gun as I apply a bit of pressure on the prop.
This method seems to work pretty well for me.          Regards, Phil

ZGlad to be of help, Robin