As above it's fine, for law or otherwise.
Outside of law, biology and geography may be a stimulating combination for going on to e.g. human sciences, archaeology, anthropology (especially biological anthropology), or some more conservation/ecology oriented bioscience courses (which accept only one science course) or some more evolution/biologically oriented earth sciences courses (such as oceanography or palaeontology), provided you meet the requirements in terms of science subjects. I would note that while most STEM courses expect two core sciences/maths at A-level, they are widely available with a foundation year if you did change your mind from law.