Problem isnt the word I was looking for, ... can come out/off easy,
cap off, 3 screws out, jubilee off the filler neck, rubber piece removed through shroud, catch the steel ring that goes round rubber shroud(3 screws screw into it) and dont forget to fit it when putting back together

. then push filler pipe further into the tank and then rotate filler shroud anticlock 1/2" and it comes off/out, hah rotating it is the hard part as its often been on for years and rust and underseal etc, I try a couple of times then cut them off, new genuine iitem is about £8.
mike