A replacement filter by 'Mann' has part Number WK512.

Although the fuel filter should be changed as part of the 'c' or 'extended b' service, this is not always the case.
Sometimes if you get an unknown smell of fuel, this can also be down to a failure in the fuel filter.

The fuel filter is located on the off-side, in front of the rear wheel arch.

You may want to remove the wheel for more access (recommended). Chock the front wheels and jack up the car.
Remove the wheel arch lining, it is held on using 3x 10mm plastic nuts, and 'tucked' into the panel and body.
(The rear panels are removed in the picture)

Pull the arch lining out of the way, and you can see the filter.

There are 2 pipes on the fuel filter, the flow travels 'up' through the filter.
The pipes are held on with 2 push clips.

Use a small screwdriver to push the clip in, as you pull the pipe off. Note, fuel will come out of the fuel lines, but will stop after a few seconds as the lines empty.

Do the same with the rear clip, although access is a little more restricted, you can get there if you crawl under the car a little more.

With the 2 pipes off, there are 2 small clips which grip onto the top of the filter, push these apart.

Pull the filter out of the carrier.

Take the new filter, slide into the filter carrier.

The pipes just clip back into place.

Finally refit the wheel arch liner, wheel and rear arches if you chose to remove them.