Patymum,I too loved FCH!!
Not quite sure where above information has been taken from but FCH GCSE results were fantastic, if you check out the league they came almost top in Barnet (apart from QE and Mill Hill County) and if you are judging by academic success they also had better results than Fortismere!!!
I'm not too sure about the ethos etc for Fortismere, but from friends who have children in the school have heard very mixed reviews.
FCH whilst is traditional in many senses ie uniform, traditional values, the school is extremely modern. You only have to look at the performing arts side or the music, or sports. I'm a writer, so obviously creativity is very important to me, as well as academic results and personally i think the school looks great.
The children are respectful and appear to have very nice, honest relationships with the teachers and the kids appear buzzing with energy and seem really happy which to me is half the battle.
As for location, that is taken into account if they are over subscribed but i would imagine 2 miles should be okay (i hope)! Going by what you said you should be fine.
I would advise to defo go and see Fortismere to compare, i'm visiting several schools to make sure i make the right choice but good luck!