As I say, unless my maths is way off I'm struggling to see why its scrubbing even with the arch screw removed.
I know you'd assume if you're lowered (as yours is) that it would rub more but in actual fact a lower (and therefore stiffer spring) can reduce scrub because it takes more energy to compress the spring and make the tyre hit the arch.
Ok, I'm not taking the p1ss but they are 12mm spacers and not 15mm or more right?
A side note, your car is beautiful and obviously in the best colour (mines ibis white too lol)!