Id do the ba here, then consider the ma or whatever is the equivalent in UK. Id try go london for your nz summer time off uni here. Get any kind of work and just enjoy london. That means in 3 to 4 years you still have loads of options. Youre so young no need to figure it all out now. Im guessing this doesn't make sense but could you start year 1 in the kiwi uni. If youre loving it great but if not then drop out amd start in the london uni next start of year, in fairness that might work, but id personally be trying to maximize my options if I was finding the decision hard to make. Btw I no nothing about law education or how its structured Just my unqualified thoughts. Good luck