For the brake water/stone shields, a friend once bought some for a similar aged VW Polo, and he used one of these online car parts places, maybe even one of auto doc's trading names, and they were very cheap.
Discs and pads, I've just always used ECP and bought Pagid discs and either Pagid or Textar pads - Pagid and Textar are both from the same group and both were used at the factory - maybe the group is TMD Friction. What out when dealing with ECP as with pads they tend to only stock a "short" range that covers most of the cars on the road, this can lead you to end up with no anti-squeal pads on the pads where the correct ones did have them. I had a bad habit of checking the brake manufacturer's web cats so that I knew what the stock code for the correct kits were before collecting from ECP, then having a discussion at the outlet so that I ended up with exactly the correct parts, when that failed, I "shopped" them to TMD Friction's UK sales team, as ECP at least, used to claim that they were the only official importer of these parts to UK - so as that meant that I had no other way to get the correct aftermarket pads, I had to report them, that twice ended up with me being supplied the correct parts FOC - though I had already paid for the incorrect parts from ECP, so swings and roundabouts I suppose - oh and again ECP, the ATE pads I bought for my 2000 B5 VW Passat 4Motion, were listed on the ATE website as being "Japan specific" for that car, curious or what, again I found another way out of that situation, maybe via GSF!