Outside courses first year LSE

I am about to begin the Politics and Economics course at LSE. Having a look at the programme structure you don't get any choices for courses in first year, and study MA107 and ST107 (among other politics and economics modules).
The course page for MA107 says those who are 'confident in their mathematical ability' could consider choosing MA100 over this unit.
I am therefore wondering if anyone at LSE (especially on my degree), have heard of anyone taking this option despite it not being an explicit choice in first year.
Obviously there are some roadblocks to me taking this module, primarily the fact that MA107 is only a half-unit, meaning taking the full MA100 unit over it may be too much both for timetabling and pressure.
Secondly while I have an A* in A-Level Maths, I don't have a an A-Level in Further Maths as my school didn't offer it.
With all that mind, would it be worth speaking to tutors when I arrive about the possibility of taking MA100?
And if I'm not able to take it in first year, is there much point in taking it in third year as an outside option?