how to remove stiff tap handle (single lever mixer tap)?

i have a single lever mixer tap for my kitchen sink however the handle it's becoming very stiff to move.
on the top of the handle there is a 'brand' section which can be opened and there is a screw (not allan key type). i unscrew the nut but the handle still doesn't come off. do i pull it up or turn the handle left or right? tried anything but not successful...

michael
August 2009