Switching courses at LSE (BMS to Maths and Econ)?

It's easy to switch at the beginning of 2nd year, just make sure you take Abstract Maths in 1st year and do reasonably well in all exams (i.e. try to get 60% in all 4 exams). Then when results come out at the end of 1st year, you can ask to switch and they'll let you. I did this myself back in the day.

They usually won't allow it in 1st year because they can't be bothered with the admin (crazy, I know).

I'm currently holding an unconditional offer for Business Maths with Statistics (I'm currently on my gap year).

Over my gap year however, i became more and more interested in Economics and now want to switch to the Maths and Economics course.

I'm worried because although the courses have the same modules in first year (providing i pick intro to abstract maths), they are in different departments and so i'm guessing this would be much harder to do?

So what would your advice be? Speak to someone as soon as i arrive in LSE?

If so what is the process of switching, will they give me conditions/interview me?