I'm not sure how to just remove the filler door.
But, if worse comes to worst, this is for overall Fuel filler bowl removal:
-- Open fuel filler flap.
-- Remove right hand rear wheelarch liner.
-- Disconnect harness connector from solenoid.
-- Unclip drain tube from retain clips pressed into chassis.
-- Remove fuel filler cap.
-- Pull down fuel filler neck grommet from the base of the bowl assembly.
-- Press in the 3 moulded retaining lugs that located the bowl assembly to the rear clamshell.
-- Carefully rotate the bowl assembly and tilt to withdraw from clamshell.