Changing the fuel filter on an XJ8L is a practice in DIY games.

First jack stand the car so you can get under it or put it on a lift. Then locate the plastic shield that covers all the fuel related lines under the left (drivers) side. This runs from the back of the front wheel well to about the left rear passengers door. It goes from about 8 inches to as much as--maybe-- a foot wide and is held to the under cage of the car by about 8 or 10 (I think) it was a 10 mm socket, nuts with washers and just plan small bolts.

The filter is towards the front of this cover, so you'll have to remove all these nuts and bolts. Since you didn't remove the front wheel well liner, you'll have fun with the front nut of this cover--I did. Once the cover is removed, the filter is covered by a slightly rusted metal shield, which is held on by three 10mm bolts. (One good thing about the whole operation was that all the nuts and bolts were the same size). This shield also has a spring clip on the filter side which clamps over the filter to help hold the thing in place (the only thing that does, with the exception of the fuel lines themselves.

Pull on the fuel line just to the rear of the filter and this should remove the plastic-- (Boy, Jaguar sure uses a lot of plastic. Seems to work in most places, so not to complain)--clamp that holds the fuel lines in place about 8 inches to the rear of the filter. Just snap this clamp back on when your through. This will give you enough room to pull the lines low enough to remove them from the filter. Oh yeah, you'll need a number of wrenches to find the ones that fit the nuts on the filter and lines. None of my MM stash would fit the filter nuts.
Hint: to find the wrench that fits the filter nuts, take it out of it's little box and do this before you start. You'll see that these nuts are fixed (don't turn), so the only ones that turn are the two on the plastic lines. These lines are PLASTIC so use caution. It would be hell to pay if you mess these babies up.

After you successfully complete this little task of replacing your new filter---oh yeah---when putting your new filter on the plastic fuel lines, be sure you put it on with the arrow on the filter facing forward. Use a little less Ham Fist pressure when putting the lines in the filter and tightening the nuts, just good and snug will do the trick. Anyway, when your complete, before you button up everything, crank up the engine and get back down and have a look see, to be sure there are no leaks. If none, then put the little slightly rusted metal shield back over the filter, button everything back up, take the car off the jacks or lift and go play a round of golf or, first, go take a good bath, you'll need it.

Cheers