I had a thought last night. It is possible that the ABS was working previous to my rear brakes being changed. It is a faint recollection, but I think I recall it being the case.
Well the first time it skidded, it was dry. All my subsequent tests have been in wet conditions to reduce damage to my tyres. By "break a bit of traction", I mean a light skid, not heavy. I definitely have a problem! I've booked it in with Audi as I'm out of ideas!Not sure I understand what you mean by "break a bit of traction". If you bring it up to about 30mph (48kmh) and slam the brake pedal down on dry pavement your ABS should kick in. If not you have a problem. Hope you work it out!