Bill the bear: Depends on the source of "estimated". I consider my conversation with dealer and VW UK only an estimated date. Until they can categorically say "it's getting built next week" I don't consider it confirmed. Quoted week 26 for me is still only a provisional week as far as VW UK are confirmed, although they admit that it should only be brought forward at this point if it moves at all.
Still, an "estimated" date for an order that's come from the dealer's mouth which hasn't been amended in the meantime is probably as "definite" as you can get right now.
Based on estimated dates, are you seeing anything like no-one with ACC or sunroof getting a car made before week 32 etc? I think I may be amongst the earliest BW for a GTD from my recollection of other postings.
I get what you are saying. However, at least four people who give me the entire order number have "BW confirmed" showing on the website, yet only one of them could give a confirmed BW in the survey. Their dealers should be able to in these cases and from people who haven't responded yet or didn't give the full order number there must be even more than four!
I'm the only one who has ordered the sunroof and my order is "estimated" at BW37... by far the longest wait I think

. That is the only option so far which seems to cause a delay, but I need more data

.
I don't really want to drop the sunroof on a chance it might bring my order forward a few months. I don't really mind waiting in theory, but I'm not keen on the prospect of sitting here for another two months while everyone else is posting lovely pictures and driving past my office window in their shiny new cars! I didn't expect to be the only one still not built by mid September. I actually ordered earlier than most people who filled in the survey! haha