If you need to remove the fuel filler flap for a paint repair or the seal has disintegrated then it can simply be removed without the need to remove the whole fuel filler itself.
Open the flap, and look down at the flap. You can see a gap at the top that the arrow is pointing to
Then you need to use a small tool to press the tab inside. This is the tab inside the flap (Flap has been removed).
Here is the trim tool I used to depress this. this is the flap itself.
Once the tab is depressed the flap needs to be pulled up away from the car by about 5mm and it will come off.
NOTE: the whole fuel bowl is a Jaguar part, the number is printed on the back, maybe C2P22913