Ultimately, I feel people will always want to travel, and as broadly as they can reasonably manage. That's not to say capacity needs will remain entirely predictable.
I feel London's likely to remain the primary UK hub, simply on the basis that economics pushes toward that kind of concentration of routes, for a modest number of larger international (or rather, intercontinental) hubs. With something like 1/6 of the entire UK population in the greater London area, and a great deal of commerce too, it's probably a safe bet that it'll remain the top UK tourist destination for international visitors. (Number two? Bath)
Things can certainly change, of course - if it's easy enough to get from one spot in the UK to another, the ultimate destination within the UK doesn't matter as much, so the airport locations can shift around. Probably not to the point of swapping positions in the list of popularity, but more of a leveling.
I'm keen to see how Skylon
develops. The SABRE engine's the revolutionary part, particularly the cooling mechanism, which is required to cool the incoming air down dramatically to a usable temperature, despite the extreme speed. The result is a craft able to place payloads into orbit, without needing to carry nearly as much propellant on board, with consequences for pricing: "the cost per kilogram of payload carried to low earth orbit in this way is hoped to be reduced from the current £15,000/kg (as of 2011)] including research and development, to around £650/kg."
Of course, plenty can happen along the way, but it's an exciting project regardless - the first genuinely new engine design in quite a while. British, too - it'll be interesting to see if it remains so, or gets bought out by the likes of Boeing.
As for a VTOL passenger craft, there was indeed the Fairey Rotodyne
. It worked, but funding was cut, leading to its cancellation in 1962. It was apparently very loud on takeoff, unfortunately, but perhaps a new take on it could address that - I'm no aerospace engineer.