Mine seem to be working a little hard.

This is the RHS, LHS similar. From what I can see, there are minor marks/cracks in the surface of the disk. They don't seem to continue right to the edge but it difficult to see. I've done 7750+ miles since I bought the car. There a definite lip on the disks too.

J.

Mine had a lip on it. Apparently dirt had caked on the pads and pulled them out of alignment so only part of the pad was touching during braking.

Ended up making a horrendous noise whenever I used the brake which is what alerted me to it.

New discs and pads was the fix. Looks like you may be needing the same?

what you can see are not cracks, they are simply pad shaped marks from where you leave your handbrake on, they all look like that and are nothing to worry about, mine look like that after 24,000 miles, still work as good as new, and the pads still have loads left. I don't expect to have to touch them for the 60k that I'm gonna keep the car........

edit: just read morts post and had another look, the lip is much bigger than on mine though.......

Spot on Sharky, the brakes are fine.