Well the fronts are on! I didn't realise 4 bolts could take so much time up, I was hoping to get the rears done as well but with me needing the car tomorrow for work and not knowing how hard they'd be, I just thought I wouldn't have enough time if they took as long as the fronts so they'll be getting done on Thursday/Friday on my days off.
The bottom caliper carrier bolt on both sides might as well have been welded in, heat nor an air ratchet gun that I had to buy from screwfix wouldn't shift it and I had a few brief thoughts of putting everything back together and taking it to Audi to do but persistence paid off in the end and they came free with a 5 foot long bar for some leverage, once they was free everything else was a complete breeze

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A few photos before, during and after:
The 2 culprits holding up the job! I had to buy an air ratchet from screwfix to try and loosen them off and it worked for two, just not the bottom two!
The pads themselves didn't look too bad and had a few miles left in them but on closer inspection I could see the actual friction part of the pad that touches the disk was separating from the back of the pad itself so i'm assuming they were very old pads for this to happen.
I think its fair to say the discs were in a pretty poor state and had seen better days
Once the caliper and disc were removed it was time to inspect and attack the general hub area and behind with a wire brush to bring it back to life and to a reasonable standard without spending hours of prep and then spraying etc.
Hub and suspension arm cleaned up as best as it would. Hub disc surface greased.
Dust shroud also was removed, primed and given a few quick coats before going back on. Simple but effective job and makes a big difference if you get your head down to look at the wheel area for whatever reason

. I don't like spraying bolts/nuts etc so I don't mind them being rusty, they aren't on show anyway but if I had thought on then I probably would have replaced them.
Next it was time for the discs to be cleaned with brake cleaner to remove any manufacturing dirt/grease before fitting to the hub. I also replaced the small disc bolt while I was there, for the sake of 33p each from Audi it seems silly not too!
Carrier reinstalled and test fit for clearance on the new disc and pads.
Before the caliper was put back on, the pins were given a good clean with wire wool, wiped and then greased.
The caliper was then reinstalled and disc checked for free movement and to make sure that the disc was central within the caliper, carrier and pads and not to one side. It was at this point I double & triple checked all pin bolts for the caliper and also torqued up the carrier bolts.
Next and final step was to mask everything up that I didn't want to be black, and to spray the calipers whilst on the car. This isn't the most ideal way to spray the calipers but if you mask things up and even some parts of the wing then you should be ok, granted that the wind is down to a minimum to avoid any over spray.
I'm happy with the end result overall, looking back now I maybe should have cleaned up and sprayed the center hub bolt which is still rusty, however you don't see this and can and will be rectified at a later date, its just a case of taking the wheel off, wire brush and spray.
For anyone doing this yourself, the job is EASY, so easy in that its only 4 bolts holding everything together and then it all comes away but bare in mind that the hardest bolts are the big carrier bolts and if they have never been removed from the car previously then be prepared for a good battle, bare knuckles and lots of time wasted!
I decided to leave the disc hubs as they are and not spray them, if they start to rust like the usual genuine Audi discs do then they'll be getting sprayed on the car as and when.
It'll be the rears this Thursday and then that's the brakes overhauled and onto the next job
Cheers!