do not do a joint degree! It is much better to be involved in a single subject as opposed to mixing one with another. Studying one subject at a time will reduce the blending of subject contents and avoid confusion where you are trying to explain physics in french!

My best piece of advice would be to do a paid placement year if you can, it will change your outlook on the world and mature you beyond words also it is so good to return to uni after summer having some money in your bank account!