So, it takes 5 minutes maximum to google search what A levels are best suited for Law. It takes 0 seconds to acknowledge, of course law is a decent degree due to the prestigious reputation it has around it, which obviously made you choose it as an option in the first place.
Let's be honest, if you're expecting to go ahead and become a lawyer and expect to love your job and work, it most likely is not going to happen. Majority of people choose it for the average annual salary, in which case isn't even accurate as there are loads of different types of Lawyers that specialise in different branches. Humanitarian for example would earn considerably less than a corporate lawyer.
As someone has already said, Lawyers are not in demand at the moment and the number of which are supposedly going to grow over coming years.
I take English Literature, Medias Studies, History and Sociology and instead of being one of these kids that decides, "Lawyer/ barrister is a well known and high paid job ill be that", I took time out to research the subject I have with my passions. For example, I'm good at speaking in person, (although I can't at the moment) would love to learn new languages, and I want to travel. Perfect Job for me is a Public Relations Executive which is paid just as much as some Lawyers, growing in demand and get paid to travel around the world representing a celebrity or company.
My advice is don't be one of these narrow minded people that just chooses a subject because its prestigious, really put thought into what you want to do and where you want to go.