Rear Brakes

I am looking at replacing my rear disks and pads on my 03 plate vRS as I have a grinding noise coming from them, its quite loud in reverse rather then forwards but is still there going forwards at low speeds. I know these calipers have a tendency to stick so as my pads/disks are low anyway I am going to replace them and look at the caliper at the same time.

Does anyone know the best place to get them from or have a part number for the disks and pads that I could order from my local Audi or VW dealer (no Skoda dealers near me lol) as I would like to stick to standard, well disks anyway?

Thanks