Remove top bumper screw cover, either side, by unscrewing black torx screw. (Photo shows non standard fixings)

Remove black torx screw resident under both covers.

Remove torx screw either side of bonnet latch. (Photo shows non standard fixings)

Undo under-tray bolts to rear of chin spoiler.

Undo black torx screws from top section of wheel arch cover and fold cover back (no need to fully remove)
These two nuts (both sides) are all that is now securing the bumper assembly. Undo nuts. As you don't have a good view of the nuts at this stage the following 2 photos will help show what you are dealing with.

Bumper assembly bolts.

Receiving holes for bolts.

If you have xenons remove headlight washer hose from supply valve by removing white clip.

Detached bumper assembly.

Unscrew final 2 bolts to grille. Prise a couple of grille clips out of retainers on bumper assembly with a screwdriver. A number of firm pulls of the grille will then free the remainder of the clips.

Reassemble in reverse order and you have this.