Uni Choices

Hi, I've applied to Queen Mary, Kings, Bristol, Bath for Maths and Warwick Maths and Stats. My predicted grades are A* A A in Maths, FM and religious studies. I've received offers from Kings and Warwick and was thinking about switching Queen Mary or Bristol to LSE Maths with Econ. I know LSE is very competitive and ps holds a lot of weight for them but my ps is all maths with a very small section talking about a project I did on game theory. I would also be eligible for a contextual offer but obviously its not guaranteed. I would really appreciate any advice on how realistic it would be to substitute one of my choices for maths with econ at LSE. Thanks!