In Malvern College, I moved from another English school (I’ve been studying in England for the 7th year already) to prepare for the university: my former tutor showed me the ratings of preparatory programs, and we decided that it was the strongest preparation for the university I needed. The school itself is also highly rated. I hope that reputation will play its role.
I have an A-level program for two years. There are very few subjects - I have a humanitarian bias, so basically languages and history. You choose all the subjects yourself, which is a plus for me: not only do you save time on unnecessary ones (like biology), but the group is chosen as strong as possible, the guys are all interested in studying a particular subject. For example, in the previous school in English, I was actually the first in the class, bypassed, according to estimates, even the British native speakers — and then everyone got up just as well and often better than mine. It only motivates me personally, but less confident students will probably be uncomfortable.