I was asked about FM by @SolitudeAtAltitude several pages back
this is what happens when I paint outdoor furniture instead of MNetting 
Ds LOVES maths and got a very secure 9. He also did statistics for GCSE and got an 8. As part of statistics they did FM but not enough children had grasped the statistics course meaning the teacher had to drop the FM bit and concentrate on the statistics.
For A level, they do maths for the first year and then FM in the second year and take both A levels at the end of year 13. He won't be doing a EPQ because of the 4 A levels.
As I am usually about 1-2 years ahead in planning stuff for Ds (he directs me, I am an English Lit degree person, he loves maths/physics/computer science) so if I remember correctly if he wants to take physics for degree they spend the first year covering FM stuff. Lots of colleges don't offer it so it is not down as a requirement but is seen as beneficial.
But Ds is very motivated eg he completed his sixth form "homework" that they set just after they got it, he is teaching himself guitar and he loves learning new stuff. He took German for GCSE and got an 8, Ds2 is doing French so Ds1 is learning that "for fun" he is also learning a bit of Spanish
hence why we think he can handle the 4 A levels.
We looked around his sixth form in both year 10 and 11 and enquired about FM at the time.