The common Entrance exam for boys at UK prep schools entails an exam in every subject, ie all sciences, Latin, religious studies, maths, history, a modern language etc . Tonbridge usually says that it requires boys to get an average of at least 62% which is high but not outstandingly high. Other boarding schools vary from about 50% to 70% average but I have heard that Tonbridge unlike other schools is quite rigid and that no exceptions are made for boys who say miss the mark by a few percent. As your son has a place at Habs he should be more than capable of the 62% as long as he is at a decent prep school. Thus its not so much a case of difficulty just that it will involve quite a lot of work over the next 2 years . Tonbridge certainly offers more flexibility if your husband may be posted back to Hong Kong , the alternative is to move then but this will be more disruptive. Your choices of boarding school will be curtailed and limited to almost certainly below the top tier. Thankfully Tonbridge itself has good transport links particularly trains to central London so you should be ok as long as you are not too North. Habs is not significantly more academic than Tonbridge just a little I would say , they both have about the same percentage of boys going to Oxbridge if that is one criteria you want to use. I don't think that should be your overiding factor as your son will thrive at both. Both have some outstanding pupils although of course Tonbridge is more international whereas Habs attracts a more North London crowd which in itself is very mixed , Asian, Jewish etc. Just to add if my son's prep school is anything to go by Tonbridge becoming very popular ! We are the wrong side of the river to send any to Habs but I have a nephew North of the River !