Only one side has the issue, please see the attached image

I can't feel any difference in performance :\

Its the first time this has occurred

Any help/input would be great

thanks peeps

My Fabias brake were is Verry similar

If you mean the rusty band... The disk is probably lipped and maybe the pads aren't moving as freely as they should. Looks like a minor version of what happens to most rear brakes. As the rusty bit builds up over time it'll migrate inwards reducing the brake area diameter and braking performance. If you're extra lucky it'll start rubbing/grinding/squealing too.

If you take the pads out you should see that they are eroded at the outside edge by constant scuffing on the rusty bit.

Thanks for the input vindaloo, I kind of understand the issue slightly better. I have tried braking slightly harder but the rust is still there : /

I hope a trip down unit18 will help ; )