Yep ali, that's the beggar!
Easiest way that I find to do it is by removing the complete unit from the inner wing - thus:
1) Remove both fuel pipes on the filter head. Don't lose the copper washers - 4 in total!
2) Unclip and release both wiring multi-plugs. Note their orientation.
3) Remove the two captive bolts that secure the filter head to the wing.
4) Lift out the complete filter assembly.
5) Carefully grip the filter head in a vice, (or Workmate etc), and unscrew the filter from the head.
6) Fill the filter with fresh fuel, and screw it back on to the head. Don't go mad, just screw it on firmly.
7) Keep the unit vertical, and carefully refit it to the wing.
Reconnect the wiring and pipes.
9) Now slacken-off, (say a half-turn), each of the six injector pipes at the injectors.
10) Crank the engine over, until you see diesel spirting from the injector pipe ends. Don't get close, as this is high pressure stuff here!
11) Once fuel is seen, stop cranking, and tighten the injector pipes.
12) Turn the key, allow the glow-plug light to extinguish, and voila, it should start and run.