It doesn't matter if you apply now or later, i did my intital tests back in november and found out 10 days later i'd passed. You don't have to sit the final interview within 3 weeks of passing the first round. My final interview is next week and this was my choice. If successful im not going to be available to start at the college until january 2007 as im in my final year at uni at the moment and having got this far i am not going to quit. I explained all this to HR and they were perfectly ok with it. So your best bet is to just be honest and explain your situation.