I did law and history and they both helped, history especially because you need to remember large amounts of info and have the ability to contstruct and sustain a convincing argument.
Doesnt matter, but I'm a fan of history. Writing an essya, problem solving etc all good. Do the subjects that will get you the best grades. Try and stick to established traditional subjects for at least two.
There are people who take law with all STEM. Though many people might push you towards English/History as absolutely necessary in order to get on an LLB, this is not the case. But I do feel that an essay-based subject might help you in providing a degree of comfort when it comes to writing your undergraduate essays.
There is no perfect or necessary combination for law.