So il start from the beginning,
About a year ago My 4.2 supercharged blew a high pressure line,
I had one made up from a hydraulic shop and had a faint whine at idle so bought a cheep pump it was very noisy was taken back off the same day (lesson learned will work for anyone else but yourself)
Original pump was refitted and just lived with the noise as no one could tell unless i pointed it out,
So eventually i gave up and bought a genuine new pump at over £700
6months later noise again i also had a stiff spot if i turned slightly right, at this point one of the control arm bushes was very shot,
I sent it away for paint got it back
Fitted all new genuine parts
Belts,
Pas pump again at eye watering cost
Pump to rack feed and return lines
Bottle and pipes from cooler too bottle and bottle to pump,
All control arms and balljoints and inner and outer track rods,
Front Pads, discs,
And an alignment,
No play in the column ujs

Fast forward to 2 days ago (a month later)
Notch turning slighly right is back,
Idle whine powersteering wise is back,
No powersteering assistance at all at idle or if im turning coasting the break (idle speed)
Over 1000 revs its perfect steerings nice and light below 30 stiffens a little more above 30 so id say the servotronic valve is working,
The notch won't appear if im over 1000 revs and turn slightly left before turning right, (most of the time)

My thoughts are its rack related now, possible blockage?

Sorted, filter in bottle was blocked