UCAS and extra A-Level during Gap Year

Hello. I am an A2 student and I am applying to university for a deferred entry (gap year), I have mentioned on my personal statement that I want to do a gap year to do extra study and self-teach Further Maths A-Level. However I dont know if and where I have to put this on UCAS? And will my offers depend on my FM grade that I won't get until August 2017? I don't understand if I will have a guaranteed space at a university by the time I get my A2 results or do I have to wait an extra year for my FM grade :/. Also how do I put on UCAS that I want to take a gap year, do I just mention it in my personal statement? Thanks.

You can't put it on UCAS until you've entered for the qualification, and you can't do that this early. You won't be able to use it to count towards offers so you need to ensure that your other grades will meet their entry requirements.

Ohh okay, so can I just mention it in my personal statement and thats it?

Yes, but consider why you're putting it there. You need to think about why this will help with the uni course - they're not just going to be impressed easily. It does depend what the uni course is as to how it can help, but you can use it to show your dedication to the subject, or some personal/study skills. You can't just put "I'm going to do this" and move on. You could say "I love maths, so to show I love maths, I decided to do this" (or "I love statistics, so decided to take this further by...") or "working on my own will improve my organisation skills".

Basically, give the information a reason to be there.