For the most part my dealer has been quite good keeping me updated, I usually get an email once a month telling me which build week has been provisionally booked. Needless to say that has always been different and further out than the previous update. On about two occasions it moved closer by 1 or 2 weeks, and then next update goes further out. I've kept a spreadsheet with all the dates and I'm sure in years to come I'll look back on it and laugh.
Regarding VW UK, I did escalate the issue around November last year, and now I get a customer relations manager that emails me as well with weekly updates. It has been quite funny seeing the 1 week difference between the two sources, not sure if they work from different 'week' calendars, or maybe the dealer is 'padding' it a bit. With the emails from the VW UK guy, sometimes it comes from his VWUK email address, and other times from his AudiUK emails address, so he is obviously covering both brands!
My last updated provisional build week was for May, but I've been close before and it suddenly moved out by a few months, so not counting on it until I know it's on a boat coming over.