If the college is anything like it was when I was there, if you want aerodrome make sure you make it known to everyone that you want to do area and vice versa. If you want a posting to Scotland, make sure you tell everyone you are set on going to Swanwick.
As far as streaming goes, we were told the decision was based on how we performed on our introductory course and apparently it even went as far back as our testing day/interview results. I don't know if the same still applies but with such an early decision it must be fairly random rather than selective.
Best of luck at the college
