I have a 06 bfmk2 xr6 and I don't have any issues up around the wheel arches but I get a bit of a mess coming up under the bottom of the tailgate of mine, as there is a bit of a gap there, but my brother in law had a fg and his did the same thing as yours, he just sealed it up with sikaflex and it was fine. not something you should have to do, but it fixed the problem