[Watsey]

M-Performance brakes had a rep for soft pedal, and it wasn't cured by coding big brakes in the relevant module.

Hopefully you spotted that you were running low on brake fluid before the level dropped below critical in the brake fluid reservoir. You really don't want to have got air in there.

There are two bleed nipples on each caliper. Bleed from the inner nipple first (nearest the dust shield), then the outer. Continuously tapping the caliper with a rubber mallet as you bleed it is a good way of dislodging any small air bubbles that may be trapped.

Once you're certain that the braking system is fully bled, you should bed the brakes. The surfaces of the pads and discs need to have been properly settled/mated first, just through normal driving for (say) 50 miles.

You're going to need a quiet stretch of (ideally) straight road for this.

Warm the discs and pads by doing some light-medium braking.

Do 10 consecutive (back to back) hard stops, 60mph down to 5mph, almost enough to trigger the ABS. Do not allow the car to stop. Immediately you hit 5mph, accelerate back to 60 and repeat.

The discs and pads will get VERY hot. You should expect some smoke, for them to smell very hot, and ideally you want to see a blue-ash tinge on the faces of the discs (which you'll only be able to check once you've parked the car).

Then go for a LONG drive, probably 20 miles, to thoroughly cool the brakes. Plan your route so that you won't need to bring the car to a stop, therefore avoiding very hot pads creating localised thicker pad deposits on the discs.

Once the braking system has been thoroughly cooled you can return home and park it overnight to cool to ambient.

I wouldn't worry about the unswept area on the discs in your photo. As long as the pads have been fitted correctly it's just indicating that the pad contact area is slightly smaller than OEM. Some pads are chamfered to aid the pad mating/bedding process, but this is normally only on the short edges of the pads (i.e. not along the longer radiused edges).