To test the transmit / receive LEDs built into the keyfob, point it at a reflective surface, about 10mm away, and hold down the “unlock” button. After blinking the LED a few times it will light up continuously to confirm that all is well. To verify that it really did do the test, try it again without pointing it at a surface (just point it into space somewhere), and the LED stays unlit after the initial blinking.
I carried out this repair ages ago. Although you could still select reverse (and all the other gears), my reversing lights didn’t work, and my passenger side rear view mirror didn’t dip.
Replacing the fuel filter is a fairly easy job requiring a minumum of tools. It will probably take you about an hour.
If you ever need to connect an aftermarket amp to your head unit, it might be useful to know the pinout of the amplifier which you will find behind the carpet trim on the left hand side of the boot.
You might need to remove the lock barrel if you have a problem with it or you are changing your locks. If so, this is how you do it.