I picked the van up this evening. Everything was fine. 2nd service went ok, needs servicing every 2 years. ( I will from now on get it serviced every year I think)
Re the update. They have now installed the latest VW adblue update, so fingers & everything else crossed, this should cure the eml. I will let you know if it comes back on!
I queried the original diagnosis which was to replace the NOx sensor. They said that with the info their equipment was giving them, that was the problem & any garage faced with the same situation would have taken the same course of action. Anyway, they charged me £60 for the update, normally £120 & if it does resolve the issue, that will be great.
He also said that the part number for the NOx sensor had changed a few times, which "might"suggest that VW realised that there was a problem with it, & then issued the update, who knows!!
Here's hoping this is my last post on this issue.