Hi.I had a warning to top up the def fluid at 4884 miles to refill with a max of 12 litres.I put in 10 litres as I did not want to overfill.This gave me a further 5000 odd miles to the next warning.Filling up was easy as the container had a flexible spout.
Just had my Adblu topped up at the dealers for free as part of the service plan. It was saying I had 3500 miles left before it needed filling but as I was visiting Canterbury and the dealer is near the centre I asked them to fill it up.
Although I suppose this info is only useful if you have the service plan and your Dealer is near to where you are!
It's no problem to do it yourself and you can buy AdBlue quite cheaply from Aldi and the like. What is useful is buying a smaller 2 litre bottle with a special non drip nozzle and decant from the bigger container so you can lift it up easier.
My refill message came up right on the suggested consumption level of 500 miles per litre so I was happy with that.
Done mine myself using the Halfords pack. The supplied nozzle makes it easy provided you can lift and tip the container which - as others have observed - is heavy when full. However, after a few seconds enough has emptied into the car to make the job more manageable.
I don't know that the weightlifting is sufficiently strenuous for me to need to decant into smaller bottles but others' experience may be different.