@Sostenueto - sorry to have given you the wobbles, but I thought I should 'throw it out there'.
There's a really good A Level selector on the Which University site. You pump in the subjects and it shows the careers/degrees it could lead to. You can then click on another button and it loads up the Unis offering the course, the grade requirements and the % of applicants receiving an offer.
My nieces school is telling them to continue with 4 until the end of year 12 and then drop to 3, however they don't take an AS -the kids are getting nothing for a years work other than the distraction from the 3 they are continuing with. Really really bad advice (I don't think they have caught up with the impact of the new Linear A Levels and are just doing what they have always done).
Probably a bit late now but we found the Target Jobs web site really useful because it has a MASSIVE list of job descriptions (On the career advice tab). There's a pile of Careers I didn't even know existed. It then tells you the degree you need so you can work back from there.
Naturally I put together a spreadsheet that showed the optimum A Levels choice to keep as many of the options open....
......and then a month ago she did a 180 and I threw it in the bin!!!