Got the message up last week, filled up today on 10k miles with it saying I had 1300 miles range left. Tank is 24L and it took 18L to brim it.
Used HGV pump at local Shell station, couldn't be easier. £12.58 for 18L. I can manage that one every 10K miles.
Just put in 18.55 litres for £12.97 at Shell Hickstead using the dedicated Adblue pump (approx 10,000 miles on the car). Dead easy to do and just like filling up with fuel. Stopped at the first click-off as per the instructions.