Hereford Audi were supposed to have fixed it before I picked up the car but they didn't quite get it right.
I booked it into my local Audi dealer (Nottingham) and they bled and re-pressurised the system today - the car handles so much better now. This coincides with me getting some 99 octane in as well so I'm all

The pressure was down at 5 bar before but is now up to 16 bar.
So a

Have to say the loan car i had (2010 A4 TDi) didn't seem to have as good build quality as my RS4. Are standards slipping or is this an effect of recession cost cutting?