The circle bit on the handle is not removeable.
There is a small surclip in behind the winder handle holding it onto the splines. The easiest way i found was to wind the window half down, push a small flat bladed screwdiver in behind the handle and move the handle to try to catch the surclip on the end of the screwdriver. When located slowly wind the window until the surclip pops off, BEING CAREFUL NOT TO LOSE IT AS IT WILL FLY A FAIR DISTANCE.
Then the handle will just pull off followed by the interior door panel.
Hope that helps