Thought I may as well update this too.
Finally got to the bottom of this one.
The problem was the brake booster. It was leaking air.
I kept hearing rushing air, till I applied brakes. VW in NZ said that is normal no matter how much I complained.
Well they have finally given in. New brake booster is on it's way. Should be here in another 10 days.
Car is driving fine the Dyno proved that.
But should see hopefully a little more boost. Maybe 1-3 psi and in addition much better fuel consumption.
Thanks for everyones help with this one.