My other car is a MINI!!!!
nope, A3 is no different to S3, especially not since I've got an S3 rack, arms, hubs, and wishbones, droplinks, struts, everything! :P
To get the clip off, go full lock right, so it's not stretching the boot. Reach round over the driveshaft into the bay to undo the clip, and you've got a surprising amount of access.
Undo the clips on BOTH ends of the boot, and you can slide the boot along the arm right to the track rod, making the nut completely visable.
On full lock left, you'll be surprised at just how far out the nut is, it's well beyond the edge of the subframe, making it easy enough to get to. I just changed mine last week, took about 10 mins per side.
Give it another shot when you get a chance, be patient with it, and it's not a bad job