You have been studying French for so long and now have to demonstrate your results in a dissertation en Francaise. At a glance, your mission seems to be double complicated. You have to work on a very serious project and this project should be written in one of the most complicated languages.
That is great if you decided to get a BTEC National Diploma! Hope you have weighed all pros and cons and your own abilities. The thing is that you will have to work rather hard, complete many BTEC National Diploma assignments, and show solid knowledge to get your BTEC Diploma.