The consumption rate I have seen quoted is 1 litre/1000 km so the tank should be good for 10,000 miles. Not sure if this is before or after the defeat device software has been removed.
Following on from my original post - I’ve just had the car serviced and after plugging it in to their diagnostics I was told it’s used 49% of its Adblue - so that’s approx 8 litres of Adblue for 15k miles. (The car hasn’t had the software update.)