Hello there,
I don't think the
Mk5 Ibiza has a screw, unlike the MK4 that does.
I believe the Mk5 fuel flap housing has moulded plastic clips that basically press and lock against the body panel, keeping it in place.
I think there's at least two clips at the top, then two wide clips on the far left - one above and one below the catch.
The bottom area has a recess ridge that I think just rests/presses against the panel. Once you've got the pressure off the two top and two far left clips, you'll then have to start lifting the rubber boot section off the fuel neck, while at the same time moving the hinge box section out that sits in a rectangular recess in wing panel. The whole fuel flap housing should lift out then.
I've added some photos of my
Mk5 Ibiza fuel flap/housing, as a
guide hopefully it'll
help.
Si