Three UK have been answering the same question about when they'll bring Mango to customers (as have all other operators globally), but instead of giving a time frame of their own or specific detail, they've continuously referred to Microsoft's announcement post on the Windows Phone Developer blog. We're eager to learn what the plans are for Windows Phone with Three, whether they're looking to drop support or not; but we can now rest easily knowing that Mango will be rolling out on their network in the next week or two.
At least we'll get the update. I can't see Three passing up on the HTC Titan; they sure love their massive 3G handsets.
Thanks to Christopher and everyone who tipped us!