How to change rear brake discs (300tdi Defender 1998)

Following my last MOT (last May) I had an advisory saying "rear brake disc worn, pitted or scored, but not seriously weakened". Can anyone point me in the direction of a step by step guide (photos) or video on how I should do this - I have not been able to find anything online so far. Is there a kit, or any advice on how I should do this or even if I should do any other work "whilst I'm at it". Thanks.

In addition to the disks / pads and fitting kit get the following
Grease seal for hub
Gasket for drive member
New caliper bolts
New disk bolts
Wheel bearing locknut tab washer (you should have twin locknut setup on a 98)

While you may get away with reusing the old bolts I always prefer to fit new ones as they won't be corroded and will be easier to remove next time.
Don't forget you should also clean and regrease the wheel bearings at the same time

You have asked for photos or an on-line guide, have you considered a workshop manual?
The trusty Haynes is fine and its format was laid down many years ago to allow even a novice to tackle most jobs. Step by step guide plus plenty of photos & drawings. what more could you want?

Thanks everone, really appreciated.