The figure did seem high, but I’m sure they will have conducted all sorts of surveys and modelling and things in order to get that number. They won’t just have plucked a figure out of thin air; they will have put time into these predictions and will have done all sorts of maths in order to get this figure.
I admit, though; approximately 20-25% of the UK population does seem very, very high. I know that they will want a certain percentage of foreign visitors, but even going off of WDW’s apparent percentage of around 20%, that still leaves around 12 million UK guests to visit. That’s what leads me to believe that they may have something special up their sleeves not necessarily seen in the current concept art.
As I said before at least Wonderworld had a sign put up. This is never going to happen it will keep going round in circles so people like you can get your hopes up for another few years. It’s far to ambitious that no sane person would throw 3-5 billion at this.