I was on the phone to my dealership today and they told me there is a recall to sort this. I've booked it in. I'm about due to top up the Ad Blue again and they told me there wasn't a problem with doing this.
There's also a recall to fix over-eager service indicators - see my recent post on the 'Ad blue and service reminders' strand.
Not sure when I would have heard about either recall if I hadn't phoned the dealership first.