I had this problem with my Octavia VRS, one rear ABS ring went, replaced it cleared the codes, then a week later the other hub decided it had enough too!
I would check the other rear hub, as chances are, that maybe knackered also, being the same age (I'm guessing they haven't been replaced before?).
I also sympathise with removing the rear caliper bolts, I removed them quite easily on my VRS, but couldn't budge them on the Golf, due to clearance and having a moment of weakness
I hope you get it sorted mate