Audi A6 Allroad 2015 automatic - Brake Judder

[Sibbers2008]

Purchased from a dealer all sound and then slowly brake judder started to appear. Local garage changed front discs and pads, no real improvement, then back discs and pads, all sorted. Since then I have gone to a brake specialist twice to have the discs skimmed and we have now got a new set of performance pads all round to try and reduce the risk of material being left on the discs but this is not working either.
I drive like a nun and so does my wife and like a nun on steroids as this problem has dragged on for the past two and a half years.
Calipers have been checked and they are releasing, so what can it be? Otherwise the car is great and I don't want to chop it in. Running out of options, patience and money !!

[Sibbers2008]

Nothing reported back and the brake specialist took everything apart and built it back. Tyres and wheels all good and balanced.
Juddering at the moment is coming predominantly through the pedal, which I believe is more likely to indicate coming from the rear rather than the front ?

[Sibbers2008]

no harsh braking from 70, hardly been on a motorway in the last year!