>>7111528It doesn't have a standard ball joint, it's like a peg with two grooves as the top to hold it in place. Boil and pop should work, but I honestly just pulled at it till it came free. May have used a screwdriver to help leverage it.
Because of the peg though the head will just sit over it unless you fill it in with blue tack or tissue paper. I just cut out a small square, folded it over so it was about the same width as the peg, and wrapped it around till the peg was covered, and the head popped securely once I stuck it on.