I am a university lecturer, and out of nosiness, I was seeing what the 2014 clearing situation was, with a bit of a professional eye. I was interested to see that there are many places left on some terrific courses and some excellent universities.
I spot checked types of History degree course as this is a popular subject, and DS has been muttering about applying to do it, and I found Medieval and Early Modern History at Bangor, Medieval History at Queen Mary, History, Ancient and Medieval at Birmingham, Arts and Humanities with a Foundation Year at Leeds (looks great for a wobbly student with special circumstances) and a number of interesting history-related courses at Scottish universities, who seem to be happy to take on English students as they effectively come with a fee dowry (like non-EU students in England). Aberdeen seems particularly hungry for English students. All of these places would be great experiences and you would leave with a valuable degree.
I think the take away message from this for me was that even dropping two grades in your subjects this year need not be a problem if you have your wits about you.
From personal experience at each place where I have worked, we have let students swap onto courses that require higher offers if it becomes clear early on that they have the capability and enthusiasm to do well on another course. A Levels are only a blunt instrument when it comes to assessing potential and the ability to cope with university work.
I have also turfed students out in the first term when it is clear they can't cope, but this is almost always because they are incessant pot smokers or can't speak English properly. For the others, if they read all the books, attend all the lectures and seminars, and do all the assignments, they leave with a degree. Miss out one of those factors and you start to compromise your results from day one.
Another factor in all this is being comfortable with the level of competition. It's frustrating if all the other people on the course are less academic than you, and less scholarly, and it is also frustrating if they are all far more bookish. It's important to try to find your tribe, even if that means taking a year out while you reapply. University is stressful enough at times, without people having an academic identity crisis. There is really no rush at all. if it was down to me, I would ban anyone under 20 going to university anyway, as it's more fun when you are a bit older, and people tend to do better.
FWIW I got CDD at A Level (stopped working after I got an unconditional offer from music college, although some of the teaching was fairly flaky anyway, looking back), and I went on to have a pretty serious academic career and have worked at top universities. A Levels are only a stepping stone, not the final destination.