Considering that you are way above the minimum grades for the subjects you want to study you should be fine, don't worry about French. Doing one more GCSE probably won't give you much of an 'edge', they just want to see that you do well in maths and English and considering you want to do sciences also your sciences. Don't worry too much about the personal statement thing. They just want to know a bit about you but you really shouldn't stress about it. I hope it all goes well, Woodhouse is a great sixth from and I am enjoying it a lot, best of luck to you.