The Engine Management Warning Light came on yesterday for the second time in four months, I've only had the van eight months, second-hand with 23,300 on the clock when I got it and 26,600 now. The first time VW Assist simply reset the warning as all indications were that is was a false alarm. So today I called VW Assist again and they attended and checked it out. Again most likely a false alarm but this time the technician also checked the software version and my van needed a software update. He installed the update, which I understand also deals with false alarms. Let's see how it goes now. Oh, he also gave me the form to claim eight AdBlue refills!
A quick update. It's been a few weeks now since the software upgrade and no warnings so far. I have noticed an increase in my miles per gallon though and a no diesel knocking, which I used to get as I pulled away from standing, so all seems good at the moment.