I grew up abroad and went to the local primary school and the local secondary, London is different and you will find that people travel. On my street, we have got people going to Harris Crystal Palace, Sydenham Girls, Forest Hill boys, Orpington, Kingsdale and those are the ones I know about . I don't think you should worry about it now. You should just choose a street you like with a good primary, secondary schools go up and down and it is impossible to predict which are going to be good in the future. You can move then if you need to.