When I left year 11 I was faced with the decision to stay at the sixth form of my school or to go to a different sixth form in a town that's about 20 minutes away from where I live. I didn't have to pick between doing the IB or alevels, but I was picking primarily between where I would have most success. I ended up deciding to stay on at the sixth form of my school, purely for convenience, and to stay with my friends, even though I knew that the other sixth form was better as it was specially dedicated to the sciences which is what I studied. Two years later, I have just finished my alevels at a sixth form which was quite frankly absolutely awful. There is no doubt that the teaching I received there completely jeopardised mine and my friends' results. And I have spent 2 years regretting not taking the risk, making the extra effort and going to a different sixth form. Do what you know is right, not what is easiest! At the end of the day if your friends can't keep In contact with you while you're elsewhere they're not real friends anyway. Plus if you're worried about making new friends at the other sixth form, the reality is that you will, but having only a couple of friends is beneficial through sixth form because you barely have any time whatsoever.