There's no hard and fast capacity listed, but it's better to bleed too much fluid through and be sure of fresh, dry fluid, than risk having old stuff in there.
Thanks for the advice Mike. I am planning on servicing my A2 by myself this year, so will be scouring the A2OC website for any useful info.
Maybe more questions will be on your way soon!
Cheers,
Gianpiero
In theory, the A2 with ESP needs a relatively low viscosity Dot 4. The VAG Dot 4 in 1 litre cans which can be bought from VW dealers for £8-£9 claims to be low viscosity. The fluid is yellow and the can cap is colour coded yellow.