Huw, Thanks for the update. However, a couple of things. First, if BMW is now selling cars with transmission WITHOUT fill holes, that doesn't speak well for "long-life." Remember, to BMW, *long-life is 100,000 miles*. After that, everyone should get a new one. For many, that may be the case. However, I guess I'm from the old school where cars should be able to go 200K, 300K or more.
Further, I still find it interesting that BMW coolant which in the US is basically Valvoline G-48 is still the same fluid used 10+ years ago. Yet now, the coolant schedule is 4 years rather than 2 years as previously required. With its continued use of plastic radiators and other parts, call me paranoid, but I think owners should still follow the old schedule and change their coolant every 2 years.
Moreover, at least for cars with manual transmission cars, I see nothing wrong with changing transmission and differential oil every
30,000 miles. That's what the old scheduled called for and the fluids haven't changed. Of course, I like my cars to last more than 100,000 miles....